Annotation

n.

1.

A note, added by way of comment, or explanation; - usually in the plural; as, annotations on ancient authors, or on a word or a passage.

Noun	1.	annotation - a comment or instruction (usually added); "his notes were appended at the end of the article"; "he added a short notation to the address on the envelope" Synonyms: notation, note
	2.	annotation - the act of adding notes Synonyms: annotating

ANNOTATION, civil law. The designation of a place of deportation. Dig. 32, 1, 3 or the summoning of an, absentee. Dig. lib. 5.
     2. In another sense, annotations were the answers of the prince to questions put to him by private persons respecting some doubtful point of law. See Rescript.

1.	(programming, compiler)	annotation - Extra information associated with a particular point in a document or program. Annotations may be added either by a compiler or by the programmer. They are not usually essential to the correct function of the program but give hints to improve performance.
2.	(hypertext)	annotation - A new commentary node linked to an existing node. If readers, as well as authors, can annotate nodes, then they can immediately provide feedback if the information is misleading, out of date or plain wrong.

adversaria, aide-memoire, apparatus criticus, comment, commentary, commentation, docket, entry, exegesis, footnote, gloss, item, jotting, marginal note, marginalia, memo, memoir, memorandum, memorial, minutes, notation, note, note of explanation, register, registry, reminder, scholia, scholium, word of explanation