English: sinusitis
Welsh: llid y sinysau
Subject: Iechyd
Welsh definition: Sinusitis is a common condition in which the lining of the sinuses becomes inflamed.
Welsh context: Mae angen i ymdrechion i wella presgripsiynu ganolbwyntio'n benodol ar heintiau'r pibellau anadlu isaf ac uchaf, heintiau'r llwybr wrinol, llid y glust ganol a llid y sinysau.