English: nonlinear cost
Welsh: cost anunionlin
Subject: Tai
Welsh definition: A curvilinear cost, also called a nonlinear cost, is an expense that increases at an inconsistent rate as production volume increases. In other words, this is an irregular cost that increases at different rates as total output increases. 
Plural: costau anunionlin
Notes: Mae’r cysyniad hwn yn cyferbynnu â “linear cost”.