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Webster 1913 Edition
Whennes
When′nes
,adv.
 Whence. 
[Obs.] 
Chaucer.
 Definition 2025
whennes
whennes
English
Adverb
whennes (not comparable)
-  Obsolete form of whence.
-  1380s, Geoffrey Chaucer, Cantus Troili, Troilus and Criseyde
- If love be good, from whennes comth my wo?
 
 
-  1380s, Geoffrey Chaucer, Cantus Troili, Troilus and Criseyde