Entry 1 sense Webster, 1913 Whilom /(hwī"lŭm)/ · Whi·lom · IPA /ˈwaɪləm/ 01 adv. Formerly; once; of old; erewhile; at times. 1. Formerly; once; of old; erewhile; at times.[Obs. or Poetic] “Whilom, as olde stories tellen us, There was a duke that highte Theseus.” — Chaucer.