annotation
//ˌæn.əˈteɪ.ʃən//
Noun
annotationSingular
annotationsPlural
1
A note or comment added to a text, diagram, or other piece of work to explain or critique it.
The professor added annotations to the student's essay to help improve it.
2
The act or process of adding explanatory notes or comments to something.
The annotation of historical documents requires careful research.