Yes; Article 4 of Industrial Property Law No. 6769 (SMK) expressly lists letters and numbers among the signs that can constitute a trademark. However, letter trademark registration carries a higher distinctiveness risk than a word mark: a single letter, two letters, an acronym that is common in the sector, or a number indicating capacity, size or model may not be found distinctive on its own. Strong results come from combining the letters with original lettering, a device or a distinctive word, or from proving distinctiveness acquired through use.
Below you will find when letters and numbers remain weak, how acronyms formed from company initials are treated, the effect of stylized lettering, similarity between short signs, the difficulties of searching, and a risk table by type of sign. If you are working on a meaningful name instead, we explain the general method in our guide on how to choose a brand name.
Can Letters and Numbers Be Trademarks?
They can; the law says so expressly. Under Article 4 SMK, a trademark may consist of any kind of sign, such as words (including personal names), figures, colors, letters and numbers, provided it is distinctive and can be represented in the register clearly and precisely. Letters and numbers sit in this list on the same footing as words.
A letter mark is a sign consisting of one or more letters, including acronyms. A number mark is a sign consisting of a number or a string of digits. Both can be filed in plain type as word marks, or together with special lettering and a device.
The problem lies not in what the law permits but in the distinctiveness requirement. Article 5(1)(b) SMK bars the registration of signs devoid of distinctive character, and Article 5(1)(c) bars signs indicating the kind, quantity, quality or other characteristics of the goods. In trade, letters and numbers are used very often for exactly these purposes: to indicate measurements, classes, capacities and models. The grounds for refusal are mapped out in general in our article on why trademark applications are refused.
The Distinctiveness Problem With Single Letters, Two Letters and Acronyms
The fewer the letters, the higher the distinctiveness risk. The assessment is always made against the goods and services in the application: the same letter may be descriptive in one field and distinctive in another. The first question for a business considering letter trademark registration should therefore be not "is the letter available?" but "what does this letter say in my sector?".
Single letters
A single letter in plain type runs into the distinctiveness barrier for most goods and services. The law does not prohibit single letters, but consumers generally perceive a single letter as an indicator rather than as a commercial origin. Letters used as sizes in clothing (S, M, L), as energy classes for household appliances or as vitamin names in food supplements (A, C, D) are directly descriptive for the goods concerned.
Two- and three-letter combinations
Strings of two or three letters leave more room than a single letter, but they carry two risks. First, if the string is an established abbreviation in the sector (such as "HD" in display technology or "PC" in computing), it amounts to an indication in common use. Second, the register is very crowded with short strings; there is a high chance that the same or a similar combination has already been filed.
Longer acronyms and strings of initials
Acronyms of four or more letters are assessed comparatively more leniently than one- and two-letter strings, especially if they can be pronounced like a word. On the other hand, acronyms that bring to mind a professional title, a technical standard or a unit of measurement may be considered descriptive regardless of their length.
Number Marks: Which Numbers Count as Descriptive?
A number that indicates the quantity, capacity, size or model of goods or services, or the time at which they are provided, is descriptive and falls under Article 5(1)(c) SMK. The same number may be considered distinctive in a field with which it has no connection at all.
Descriptive numbers
Typical examples are "4x4" for off-road vehicles, "7/24" (the Turkish way of writing 24/7) for round-the-clock services, "500" indicating volume for drinks, "1000" indicating power for electrical appliances, "360" indicating the field of view for cameras and "5G" indicating the generation in telecommunications. These numbers give information about the goods concerned; consumers link them to a characteristic of the product rather than to a business. Four-digit numbers perceived as a founding year are also weak on their own. Writing the number in words instead of digits does not change the outcome; a number indicating volume gives consumers the same information when written out as "BEŞ YÜZ" ("five hundred").
Numbers unrelated to the goods
A number with no connection to any characteristic of the goods may be assessed like an arbitrary sign, and its chances of registration improve. To take a made-up example, "73" for a coffee chain may fall into this group. Here the main risk is not descriptiveness but similarity: earlier marks written with the number in digits, in words or in its foreign-language equivalents may stand in your way.
When the Acronym Is Made of the Company's Initials
An acronym formed from the initials of a company's trade name does not automatically enjoy trademark protection, even if the trade name is recorded in the trade registry. Trade name registration and trademark registration are different registers and give rise to different rights. To take a made-up example, the acronym "MPD" of a company whose trade name is "Mavi Pusula Deri Sanayi" enters the protection of trademark law only if it is also filed as a trademark.
Watch three points with acronyms formed from initials:
- Other businesses with the same initials: A three-letter acronym can be the shared initials of many businesses with different trade names. The fact that your trade name begins with those letters gives you no advantage over an earlier trademark.
- The full name and the acronym are separate signs: Registering the full name does not automatically protect the acronym, and registering the acronym does not automatically protect the full name. If you use both, consider both.
- Document recognition: If your customers have known you by the acronym for years, that use will become your strongest evidence in any future dispute over distinctiveness; keep dated archives of invoices, catalogs and advertising.
Strengthening a Letter Mark With Stylized Lettering and Devices
A letter or short string that is not found distinctive in plain type may become registrable when filed with original lettering, a monogram or a figurative element. In that case, the distinctiveness is carried by the visual composition rather than by the letter, and protection is limited to that composition.
This has two practical consequences. First, the stylization must be genuinely original; making a standard typeface bold or italic, or coloring it in a single color, adds no distinctiveness. Second, a stylized registration does not grant a monopoly over the letter itself. Protection against a competitor who uses the same letter in a different rendering depends on the degree of visual similarity. We explain the steps for applications containing a graphic in our guide on how to register a logo in Turkey.
A third route is to combine the short string with a distinctive word: in a construction such as "MPD PUSULA" (a made-up example), the word provides the distinctiveness and the acronym gains recognition alongside it. A word mark is normally the form that gives the broadest protection; we explain the logic of that breadth in our article on trademark registration without a logo. With one- and two-letter strings, however, the distinctiveness barrier is most often hit precisely in the form of a plain-type word mark, and the strategy should be built around that balance.
Similarity Between Letter Combinations: Is One Different Letter Enough?
In short signs, each letter carries more weight, so a one-letter difference may be more noticeable than in long words. That is not an automatic rule, however. The order of the letters, letters that look alike (O and Q, I and L, M and N), pronunciation and the similarity of the goods and services are all assessed together.
Typical situations that increase similarity between short strings are: the same letters in a different order ("MPD" and "MDP"), letters that are easily confused visually, letters and digits that sound the same (such as "B4" and "BEFORE" when read in English), and a digit and a word with the same concept ("7" and "YEDİ", Turkish for seven). We discuss the general criteria in detail in our article on likelihood of confusion.
Short strings also have a side that works in your favor: a sign with weak distinctive power has a narrow scope of protection. If the earlier mark rests on an acronym that is common in the sector or on a descriptive number, small differences may be enough to rule out a likelihood of confusion. This is used as the "weak distinctiveness" argument at the opposition and defense stages.
The pronunciation of letters also varies by language. In Turkish the letter "C" is named "ce", pronounced with a "j" sound, while in English it is read as "see"; this difference complicates the similarity assessment, especially for acronyms promoted with an English pronunciation. We examine the registrability of foreign-language words and acronyms separately in our article on registering foreign word trademarks.
Why Is Searching Letter and Number Marks Difficult?
Searching short strings is difficult in two directions: an exact search returns very few results, while a partial search brings back thousands of irrelevant records. The right approach is to broaden the search with controlled variations. In our free trademark search tool, the results table also shows class and device information; for short strings, these two columns are the fastest way to separate a genuine conflict from irrelevant records.
The search sequence we recommend for a letter or number mark:
- Exact string: Search for the mark in the form you will file it and filter the results by the relevant classes.
- Punctuation variations: Try the versions with full stops, without them, with hyphens and with spaces separately ("M.P.D.", "M-P-D", "M P D").
- Order and look-alike letters: Search the versions with the letters in a different order and strings written with visually confusable letters.
- Digit and word equivalents: Search for the number in digits, written out in Turkish and in the languages of your target markets.
- Pronunciation equivalents: Try the written-out forms of the Turkish and English pronunciations of the letters.
- Stylized records: Also review figurative marks that use the letter inside a logo; these records do not always show up in a text search.
The detailed list of sound and spelling variations that need to be searched can be found in our guide to phonetic similarity in trademark searches.
Is It Possible to Acquire Distinctiveness Through Use?
It is. Under Article 5(2) SMK, a trademark that was used before the filing date and, as a result of that use, acquired distinctive character for the goods and services in the application cannot be refused on the grounds of lack of distinctiveness, descriptiveness or common use in trade. For businesses that have been known by an acronym for years, this provision is an important door.
The threshold is high: the duration, intensity and geographical extent of use, and the fact that consumers genuinely associate the acronym with you, must be proven with documents. We explain the types of evidence and the stages at which the argument can be raised in our article on acquired distinctiveness through use.
A practical route is to register the acronym first together with a distinctive word or logo and to build up evidence of use. In this way, the acronym gains recognition in the market as part of a registered trademark; once sufficient evidence has accumulated, a separate letter trademark application for the acronym itself can be filed on the basis of acquired distinctiveness.
Risk and Ways to Strengthen by Type of Sign
The table below summarizes the most common risks for marks consisting of letters and numbers, and a realistic way to strengthen each one.
| Type of sign | Typical risk | Way to strengthen |
|---|---|---|
| Single letter, standard typeface | Lack of distinctiveness; perceived as a size, class or vitamin indicator | Original stylization, a figure or combination with a distinctive word |
| Two letters | Clash with an established sector abbreviation; crowded register | Stylized lettering; broadening the search with variations |
| Acronym of three or more letters | Clash with an abbreviation of a profession, standard or unit; similarity with strings in a different order | Using the full name or a distinctive word alongside it |
| Company initials | Trade name registration gives no trademark protection; other businesses with the same initials | A separate trademark application; keeping dated evidence of use |
| Number indicating capacity, size or model | Descriptiveness (quantity, characteristics) | Pairing the number with a distinctive word |
| Number unrelated to the goods | Earlier marks written in digits, in words or with foreign equivalents | Searching all written forms |
| Letters + digits that look like a model code | Consumers perceive it as a series or model number | An original structure that moves away from the look of a code; a figurative element |
| Acronym in use for a long time | Descriptiveness objection | An evidence file for acquired distinctiveness |
Summary
Key points to remember:
- Article 4 SMK expressly lists letters and numbers among the signs that can be trademarks; the difficulty lies not in permission but in distinctiveness.
- Single letters, abbreviations common in the sector and numbers indicating capacity, size or model are weak on their own.
- Company initials do not enjoy trademark protection unless they are also filed as a trademark.
- Original stylization or a distinctive word can make registration possible, but protection remains limited to that composition.
- Searches for short strings should cover punctuation, order, digit-and-word and pronunciation variations.
Shall we assess the registrability of your letter or number mark?
Share your acronym, how you use it and your field of business through our contact page. Our team, which works with trademark attorneys authorized before TÜRKPATENT (Turkish Patent and Trademark Office), will assess the distinctiveness risk, similar strings in the register and the options for strengthening the mark; once the right set-up is clear, we can handle your trademark registration application from start to finish.
