anecdote: [17] In Greek, anékdotos meant ‘unpublished’. It was formed from the negative prefix an- and ékdotos, which in turn came from the verb didónai ‘give’ (a distant cousin of English donation and date) plus the prefix ek- ‘out’ – hence ‘give out, publish’. The use of the plural anékdota by the 6th-century Byzantine historian Procopius as the title of his unpublished memoirs of the life of the Emperor Justinian, which revealed juicy details of court life, played a major part in the subsequent use of Latin anecdota for ‘revelations of secrets’, the sense which anecdote had when it first came into English.
The meaning ‘brief amusing story’ did not develop until the mid 18th century. => date, donation[anecdote etymology, anecdote origin, 英语词源]