Wanna know that what is the definition of EXPRESSION and name of some on line resources to get the usage of some expression.
Have you looked in a dictionary for the definition of "expression"? What did you find?
Please see my corrections to your post above, in red. Please don't use chatlish/textspeak like "wanna" on the forum and remember to be polite, using "please" and "thank you".
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.