This is the 948th most frequent Russian word.
регистрации
"Регистрации" in English means "registration."
The word 'регистрации' is in the genitive case, used here to describe the process being referred to.
Процесс регистрации был завершен вчера.
The registration process was completed yesterday.
The word 'регистрации' is used in the genitive case because it follows the preposition 'для' which requires it.
Нам нужно предоставить документы для регистрации компании.
We need to provide documents for the company's registration.
Here, 'регистрации' is used in the prepositional case, as indicated by its usage after 'о' to refer to the topic of discussion.