Something commonplace is ordinary. It can also be something dull and unchallenging or tired and clichéd. Coffee shops in cities are commonplace, so are berets in Paris. You see them all over the place.
Things that are common can be found all over the place — they're commonplace! The word is a literal translation of the Latin locus communis for "general topic." Commonplace things and behavior are ordinary. For example, a commonplace job is a boring, mind-numbing task. It’s humdrum and unglamorous. A commonplace word or saying is a cliché — it's so common that it becomes meaningless and annoying.