as an adverb: We went out into the garden. ♦ He took out a penknife.
after the verb ‘to be’: You were out when I called. ♦ The house was silent and all the lights were out.
in the preposition phrase out of: I got out of bed and went downstairs. In American English and spoken British English out itself is commonly used as a preposition, but many British people consider that this use is not correct: ♦ I looked out the window.