1670s, "secret or private stories," from French anecdote (17c.) or directly from Medieval Latin anecdota, from Greek anekdota "things unpublished," neuter plural of anekdotos, from an- "not" (see an- (1)) + ekdotos "published," from ek- "out" (see ex-) + didonai "to give" (from PIE root *do- "to give").
Procopius' 6c. Anecdota, unpublished memoirs of Emperor Justinian full of court gossip, gave the word a sense of "revelation of secrets," which decayed in English to "brief, amusing story" (1761).
word-forming element in nouns of act, process, function, condition, from Old French and French -age, from Late Latin -aticum "belonging to, related to," originally neuter adjectival suffix, from PIE *-at- (source of Latin -atus, past participle suffix of verbs of the first conjugation) + *-(i)ko-, secondary suffix forming adjectives (see -ic).
<a href="https://www.etymonline.com/word/anecdotage">Etymology of anecdotage by etymonline</a>
Harper, D. (n.d.). Etymology of anecdotage. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/anecdotage