[n] the most direct or specific meaning of a word or expression; the class of objects that an expression refers to; "the extension of `satellite of Mars' is the set containing only Demos and Phobos"
[n] the act of indicating or pointing out by name
The dictionary meaning of a word. Writers typically play off a word's denotative meaning against its connotations, or suggested and implied associational implications.
In the following lines from Peter Meinke's "Advice to My Son" the references to flowers and fruit, bread and wine denote specific things, but also suggest something beyond the literal, dictionary meanings of the words:
To be specific, between the peony and rose
Plant squash and spinach, turnips and tomatoes;
Beauty is nectar and nectar, in a desert, saves--
and always serve bread with your wine.
always serve wine.
extension, indication, reference
meaning, naming, substance