Words have two “meanings”: the denotation of a word is the direct equation to an object or other subject. Modern linguists use the term “signifier” to mean the word or phrase in a language that refers directly to a “signified.” For example, that delicious grape alcoholic drink, the wet, cold, sweet liquid stuff that comes in a bottle with a cork, is (in English) the signified by the signifier “wine.” In French, the signifier for that same signified is “vin.” So denotation is the dictionary definition of a word. Its connotation, however (and the word is most often found as a noun rather than as a verb, and the correct infinitive verb form is “ to connote”) is the understood “texture or “tone” or “feeling” of a word. Example: Kitten is the correct dictionary signifier for a young cat; but the connotation of “kitten” is soft, small, furry, cuddly, young. These connotations come from centuries of using the word to signify not only young cats, but softness, furriness, cuddliness, and so on. Each word takes on connotation as it is used in contexts where its emotional or aesthetic qualities are used metaphorically. The differences among synonyms are almost always differences of connotation; the law enforcer in a society who wears a badge is called a policeman, a flatfoot, a cop, a police officer, etc., all terms referring to the same human being and the same occupation, but with widely disparate connotations, some terms formal and respectful, some derogatory and insulting. Some linguists claim that there are no synonyms, because every word has a slightly different connotation.
The poet, then, chooses not only the denotation of his or her words but also the connotations, the textural impressions of a word; look at “When I have fears that I may cease to be” vs. “When I’m afraid I’ll kick the bucket” or “Oft in the stilly night, ‘ere slumber’s chains have bound me” vs. “A lot of times in the silence of the late evening before I fall asleep” You see that poetry is the careful wording of a thought or feeling or idea, carefully filtered through the poet’s sensitivity to the connotation of the words in his vocabulary as well as their sounds and rhythms. To “connote” something is to say the word that not only has the dictionary definition, but carries with it its past textures in related contexts.