In noun+noun structure the first noun is normally singular in form even if it has a plural meaning (e.g. a shoe shop, a toothbrush, etc)
However, there are exceptions:
Some nouns have the plural -s when they modify other nouns. These include:
- nouns which have no singular form (like clothes);
- nouns which are not used in the singular with the same meaning (customs);
- and some nouns which are more often used in the plural than in the singular (like savings);
- in some cases usagae is devided (sport(s);
In general, the use of plural modifiers is becoming more common in British English; American English often has singular forms where British has plurals, e.g.:
the arrivals hall (BrE) - the arrival hall (AmE)....

As you can see, it's not that strict, there are exceptions and some new tendencies that has to be taken into account.

However, I think that 'terms translation' is wrong, as there are 2 different words - 'term' and 'terms'
(Oxford Advanced)
terms /t3 mz; AmE t3 rmz/ noun [pl.]
1 the conditions that people offer, demand or accept when they make an agreement, an arrangement or a contract: peace terms Under the terms of the agreement, their funding of the project will continue until 2005. They failed to agree on the terms of a settlement. These are the terms and conditions of your employment.
2 conditions that you agree to when you buy, sell, or pay for sth; a price or cost: to buy sth on easy terms (= paying for it over a long period) My terms are £20 a lesson.
3 a way of expressing yourself or of saying sth: We wish to protest in the strongest possible terms (= to say we are very angry). I'll try to explain in simple terms. The letter was brief, and couched in very polite terms. She spoke of you in glowing terms (= expressing her admiration of you).

term /t3 m; AmE t3 rm/ noun, verb
noun—see also TERMS
1 [C] a word or phrase used as the name of sth, especially one connected with a particular type of language: technical / legal / scientific terms a term of abuse ‘Register’ is the term commonly used to describe different levels of formality in language.
2 (AmE also tri•mes•ter) [C, U] (especially in Britain) one of the three periods in the year during which classes are held in schools, universities, etc: the spring / summer / autumn / fall term (BrE) It's nearly the end of term. (AmE) the end of the term during term (time)—see also SEMESTER, TERMLY, TERM-TIME
3 [C] a period of time for which sth lasts; a fixed or limited time: during the president's first term of / in office He faces a maximum prison / jail term of 25 years. a long term of imprisonment The term of agreement can be for either two or three years.
4 [sing.] (formal) the end of a particular period of time, especially one for which an agreement, etc. lasts: His life had reached its natural term. This view of the economy is approaching its term (= it will soon be old-fashioned) (medical) The pregnancy went to full term (= lasted the normal length of time).
5 [C] (mathematics) each of the various parts in a series, an EQUATION etc.

The correct way to use it would be 'Translation of terms'.
Otherwise it acquires a different meaning or just becomes confusing.

Espero que te sea de ayuda
;-)