Welsh edit

Etymology edit

From rhaid +‎ -iol.

Adjective edit

rheidiol (feminine singular rheidiol, plural rheidiol, equative mor rheidiol, comparative mwy rheidiol, superlative mwyaf rheidiol)

  1. necessary, required

Mutation edit

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