believe in

Etymology

Calque of the Latin use of crēdō (“believe”) with in plus accusative.

Verb

believe in (third-person singular simple present believes in, present participle believing in, simple past and past participle believed in)

1. (transitive) To ascribe existence to.

   Do you believe in God? / the Easter Bunny? / ghosts?

   Since I don't believe in reincarnation, I believe that the only way to eliminate suffering is to die.

2. (transitive) To believe that (something) is right or desirable.

   I don't believe in sex before marriage.

   I don't believe in making my bed.

3. (transitive) To have confidence in the ability or power of.

   I believe in you, man! You can do it!