What term refers to the act of noting or marking something down in writing?

The act of noting or marking something down in writing is best described by the term "notation." This term specifically refers to the action of making brief notes or symbols to represent information. Notation is often used in contexts where concise and clear marking is necessary to capture specific points without extensive elaboration.

While documentation generally refers to the comprehensive process of collecting and organizing information, and annotation implies additional commentary or notes that clarify or elaborate on a text, notation focuses specifically on the initial act of writing down essential information or points. The term "record" pertains more broadly to storing information in a systematic way, but it does not emphasize the action of writing something down as succinctly as "notation" does.