Cordero vs. oveja
The Spanish words cordero and oveja both relate to sheep, but they have distinct meanings and uses.
Cordero
B1Cordero refers specifically to a lamb, which is a young sheep typically under one year old.
Comimos cordero asado en Navidad.
(We ate roasted lamb for Christmas.)
El cordero recién nacido necesita ayuda para ponerse de pie.
(The newborn lamb needs help standing up.)
Oveja
A2Oveja is the general term for a sheep, typically referring to an adult female sheep.
El pastor cuida un rebaño de ovejas en la montaña.
(The shepherd takes care of a flock of sheep in the mountain.)
La oveja produce lana que usamos para hacer ropa.
(The sheep produces wool that we use to make clothes.)
Summary
While cordero specifically refers to a young sheep or lamb, oveja is the general term for sheep, usually meaning an adult female. Cordero is often used in culinary contexts, whereas oveja is more commonly used when talking about the animal in agricultural or general settings.