Mae'r Geiriadur Prifysgol Cymru yn sgrifennu am _gwrcyn_/_cwrcyn_ mai talfyriad yw hynn ar _gwrcathyn_/_cwrcathyn_. A _gwrcathyn_ sy'n fachigyn (diminutive) ar _gwrcath_. Mae'r eileded g-/c- blaenorol ai yn gymathiad (assimilation): g...c > c...c ai yn rywbeth fel "di-dreiglad". Fe gafodd y ffurf _gwrcath_ edrych arni hi fel ffurf dreigledig am fod y gair (cath) yn fenywaidd. Felly: y gwrcath > (heb y fannod) cwrcath. Roedd y ffurf _y gwrcath_ heb ei dreiglo am ryw reswm (efallai am gael yr elfen cyntaf ei nabodd fel enw (gwrywaidd) _gwr_, neu rywbeth?). (Cf. GPC s.v. gwrcath a gwrcyn) [gwrcyn is an abbreviation of gwrcathyn. Alternation g-/c- is either an assimilation or some kind of (wrong) "de-lenition".] >( > Do you mean "cwrcyn"? Not that I dispute your linguistic talents - though > ) > this may be a regional variant. >( > ) gwrcath, cwrcath, cwrcyn -- is the last one a compound of gwr/cwr + >( cyn? If so, what is "cyn" here? > >cwrcath > cwrc > cwrcyn by accretion of a diminutive ending? Cwrc is >spoken but perhaps not often written. >