Origin and history of denotation

1530s, "a secondary signification, that which is included in the meaning of a word besides its primary denotation," from Medieval Latin connotationem (nominative connotatio), noun of action from past-participle stem of connotare "signify in addition to the main meaning," a term in logic, literally "to mark along with," from assimilated form of Latin com "with, together" (see con-) + notare "to mark, note, make a note," from nota "mark, sign, means of recognition" (see note (n.)).

Earlier it was used in Middle English medical texts for "a concommitant symptom"(Chauliac, early 15c.).

The meaning "that which constitutes the meaning of a word" (1829) originated with James Mill, father of John Stuart Mill, who also developed the use of it.

The use, which I shall make, of the term connotation, needs to be explained. There is a large class of words, which denote two things, both together ; but the one perfectly distinguishable from the other. Of these two things, also, it is observable, that such words express the one, primarily, as it were ; the other, in a way which may be called secondary. Thus, white, in the phrase white horse, denotes two things, the colour, and the horse ; but it denotes the colour primarily, the horse secondarily. We shall find it very convenient, to say, therefore, that it notes the primary, connotes the secondary signification. [James Mill, footnote in "Analysis of the Phenomena of the Human Mind," 1829]

c. 1200, noten, "observe, take mental note of, mark carefully," from Old French noter "indicate, designate; take note of, write down," from Latin notare "to mark, note, make a note," from nota "mark, sign, note, character, letter" (see note (n.)). Sense of "mention separately or specially among others" is from late 14c. Meaning "to set down in writing, make a memorandum of" is from early 14c. Related: Noted; noting.