Annotation

[Sarah]

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

[Greta]

In programming sense... it is kinda small [attribute] that you tag alongwith some definition... (may be for a method or some attribute). This directly doesnt affect how the [programme] works, but acts as set of specifications in case someone(some [framework] or something... is trying to act according to it...

[Hina Muqadas]

A note by way of explanation or comment added to a text or diagram.

[Luis Fok]

a short explanation or note added to a text or image, or the act of adding short explanations or notes: