A suckling is a young animal still feeding on its mother's milk. A suckling pig, a suckling lamb, suckling young.
Suckling pig is the commonest use, and it means one roasted whole while still on milk. The -ling ending marks a young or small thing, as in duckling and gosling, and it is one of the oldest patterns in the language.
1nounsucklingA young animal still feeding on its mother's milk.
“The mother pig lay in the straw with her sucklings pressed against her.”
suckling is a young animal.
Suck plus -ling, an ending marking a young or small creature, as in duckling.
Middle English
sukling
English, today
suckling
From Middle English sukling, sukeling, sokeling, equivalent to suck + ling. Cognate with Middle Dutch sogelinc (“suckling”), Dutch zuigeling (“suckling”), German Säugling (“suckling”).
Etymology from Wiktionary, CC BY-SA