Literary Device: Connotation

an association that comes along with a particular word. Connotations relate not to a word's actual meaning, or denotation, but rather to the ideas or qualities that are implied by that word.

Example:

I saw on the slant hill a putrid lamb,
Propped with daisies. The sleep looked deep,
The face nudged in the green pillow
But the guts were out for crows to eat

Function:

In Richard Eberhart's "For a Lamb", those feelings associated with lamb (such as innosense, peace, purity, gentleness) only highlight the ugliness of the situation. So, the connotation of the word serves to reenforce the tone of the poem.