lambkin
A small, gentle baby sheep.
A lambkin is a young lamb, especially one that's small, gentle, and endearing. You might find lambkin in older storybooks or poems where shepherds watch over their flocks of lambkins in springtime meadows.
People also use lambkin as a sweet nickname for someone they care about, especially children. A grandmother might call her grandchild “my little lambkin” the same way she might say “sweetheart” or “dear one.” The word carries the gentle, innocent qualities we associate with baby sheep: soft, mild-mannered, and needing protection.
While lambkin isn't common in everyday conversation anymore, it appears frequently in classic children's literature and nursery rhymes. When you encounter it, the word creates an immediate feeling of tenderness and old-fashioned charm, like stepping into a pastoral scene from a century ago where shepherds knew each animal in their flock by name.