Meaning of the word "by now" in English

What does "by now" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

by now

US /baɪ naʊ/
UK /baɪ naʊ/

Adverb

by this time; already

Example:
The train should have arrived by now.
You must be hungry by now.