The emotional response evoked by a word or the associations called up by a word that goes beyond its dictionary meaning.
[n] an idea that is implied or suggested
[n] what you must know in order to determine the reference of an expression
Dylan Thomas's "Do Not Go Gentle into That Good Night" includes intensely connotative language, as in these lines:
Do not go gentle into that good night,
Old age should burn and rave at close of day;
Rage, rage against the dying of the light.