а

conjunction

while; and; but
роди́тели ушли́, а де́ти оста́лись до́ма the parents went out while the children remained at home
вот перо́, а вот бума́га here is a pen, and here is a sheet of paper
не..., а... not ..., but ...
не он, а его́ помо́щник not he, but his assistant
а не... (and) not
э́то его́ кни́га, а не ва́ша it is his book (and) not yours
э́то его́ друг, а э́то его́ сестра́ this is his friend and that is his sister
по́езд ухо́дит че́рез полчаса́, а ты ещё не гото́в the train leaves in half an hour, and you are not ready yet
yet
хотя́ ему́ и о́чень ве́село, а на́до уходи́ть although he is enjoying himself very much, he must go
if
а не понима́ешь, так и не говори́ if you don't understand, don't talk
but, and (deviates from the preceding idea in some manner; introduces a new or different meaning, as opposed to но, which usually indicates contrarity)
Сего́дня тепло́, а вчера́ бы́ло хо́лодно. It is warm today, but yesterday it was cold.
Э́то не я́блоко, а гру́ша. This is not an apple, but a pear.
А что? How come?
а то or else
used in the following idiomatic expressions
а (не) то (or) else; otherwise
а так как now as, but as
а и́менно namely; viz (= videlicet)
спеши́, а (не) то опозда́ешь hurry up, (or) else you will be late; hurry up, otherwise you will be late
а так как он не пришёл... now / but as he did not come ...
щ

а | Slovarish | Словарищ