D defs.my
Entry 1 sense Webster, 1913

Whilom

/(hwī"lŭm)/ · Whi·lom · IPA /ˈwaɪləm/
01 adv. Formerly; once; of old; erewhile; at times.
  1. 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.