commonplace (n.)

1540s, "a statement generally accepted," a literal translation of Latin locus communis, itself a translation of Greek koinos topos "general topic," in logic, "general theme applicable to many particular cases." See common (adj.) + place (n.). Meaning "memorandum of something that is likely to be again referred to, striking or notable passage" is from 1560s; hence commonplace-book (1570s) in which such were written down. Meaning "well-known, customary, or obvious remark" is from 1550s. The adjectival sense of "having nothing original" dates from c. 1600.