"period during which a historical person's life work was done," 1843, Latin, literally "he flourished," third person singular perfect indicative of florere "to flourish, to bloom" (see flourish (v.)). Usually in abbreviation fl. The third person singular present subjunctive of the verb, floreat, sometimes is attached to proper names "to indicate the hope that the named person, institution, etc., may prosper" [OED].