Etymology 1Edit

From Proto-Brythonic *bɨw, from Proto-Celtic *biwos, from Proto-Indo-European *gʷih₃wós, from *gʷeyh₃- (to live).


byw (feminine singular byw, plural bywion, unknown comparative)

  1. alive, living, having life, animate, quick, existing, actual
  2. lively, full of life, vivacious, vigorous, sprightly, spirited, eager, sparkling; vivid, graphic, susceptible to


byw m (plural bywion)

  1. living person or soul, living creature
  2. living, life, lifetime; energy, vigor, vitality
  3. the quick, the living flesh, the soft part of bread

Etymology 2Edit

From Proto-Celtic [Term?], ultimately from Proto-Indo-European *gʷeyh₃- (to live). Compare Breton beva, Cornish bewa.


byw (invariable)

  1. to live
Usage notesEdit

Byw does not conjugate and must be used with periphrasis.

Roedd o’n byw yng Nghaerdydd.
He lived in Cardiff.
Related termsEdit


Welsh mutation
radical soft nasal aspirate
byw fyw myw unchanged
Note: Some of these forms may be hypothetical. Not every
possible mutated form of every word actually occurs.


  • R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke et al., editors (1950–present) , “byw”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies