Breakdown of Терминологию добавили в глоссарий.
Questions & Answers about Терминологию добавили в глоссарий.
Because it is the direct object of the verb добавили (added).
The base form is терминология. Since it is a feminine noun ending in -я, its accusative singular form is терминологию.
- nominative: терминология
- accusative: терминологию
So the sentence structure is basically:
- добавили что? → терминологию
That is why Russian uses the accusative here.
This is a very common Russian pattern. The verb is in the 3rd person plural past form, but no subject is stated. It means something like:
- they added the terminology to the glossary
- or more naturally in English: the terminology was added to the glossary
- or someone added the terminology to the glossary
Russian often uses this indefinite-personal construction when the doer is unknown, unimportant, or simply not mentioned.
So добавили does not necessarily mean a specific group of people. It can just mean it was added in a general sense.