כבש כבשים (lamb/sheep); there are fourteen times in the Torah where the letter ש precedes the letter ב in this word. And I explained that כשב וכשבים tends to be more of a species name and another species name will always come next to it, like בקר בכשבים ובעיזים (of the beeves, of the sheep, or of the goats)⁵⁸⁷. And in a place where it does not come with this meaning, it will come from the perspective of the strength of its body and its fat tail, and it will come to include the fat tail.

footnotes: ⁵⁸⁷ Leviticus 22:19.