Meaning of “wonder” - Learner’s Dictionary

wonder

noun uk us /ˈwʌndər/
ADMIRATION [ U ]

surprise and admiration:

The boys gazed in wonder at the shiny, red Ferrari.
THING [ C ]

something that makes you feel surprise or admiration:

no wonder

B2 used to say that you are not surprised about something:

No wonder she failed the test if she didn't do any work.
it's a wonder (that)

used to say that you are surprised about something:

It's a wonder he's still alive.

(Definition of “wonder noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)