Why is the ninth month called September?
1530s, "indication," from Late Latin denotationem (nominative denotatio), noun of action from past participle stem of denotare (see denote). As a term in logic, from 1843 (contrasted with connotation).
The basic dictionary meaning of a word, without its connotations. For example, the denotation of the word modern is “belonging to recent times,” although the word may have different connotations.