Real Dictionary

commonplace
A commonplace is a remark or opinion that is often expressed and is therefore not original or interesting.
A commonplace is something that happens often or is often found.
If something is commonplace, it happens often or is often found, and is therefore not surprising.

commonplace in American English
a passage marked for reference or included in a commonplace book
neither new nor interesting; obvious or ordinary
adjective: ordinary; undistinguished or uninteresting; without individuality
noun: a well-known, customary, or obvious remark; a trite or uninteresting saying

commonplace in British English
adjective: ordinary; everyday
noun: something dull and trite, esp a remark; platitude; truism