Welsh edit

Etymology edit

From perthnasedd +‎ -ol.

Adjective edit

perthnaseddol (feminine singular perthnaseddol, plural perthnaseddol, not comparable)

  1. (physics) relativistic

Mutation edit

Welsh mutation
radical soft nasal aspirate
perthnaseddol berthnaseddol mherthnaseddol pherthnaseddol
Note: Some of these forms may be hypothetical. Not every possible mutated form of every word actually occurs.