ἄρνας [1 verse] (noun pl fem acc) "Lambs" is aren, which means primarily "wool", and, by extension, "lamb", and "sheep." --  "Lamb"  is the Greek word that primarily means "wool" and, by extension, "sheep" or "lamb". It appears only once in the Gospels, here. The common word usually translated as sheep that Jesus uses as a metaphor for his followers is more generic, referring theoretically to any form of herd animal.