Table of contents Family name origins & meanings English : topographic name from Middle English flasshe ‘pool’, ‘marsh’. This is thought to be from Old Danish flask ‘swamp’, ‘swampy grassland’, ‘shallow water’. Jewish (Ashkenazic) : variant spelling of Flasch. Possibly an Americanized spelling of German Flasch. Appears on 151 Cute and Funny Nicknames for Boys