note (v.)

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.

note (n.)

c. 1300, "a song, music, melody; instrumental music; a bird-song; a musical note of a definite pitch," from Old French note and directly from Latin nota "letter, character, note," originally "a mark, sign, means of recognition," which traditionally has been connected to notus, past participle of noscere "to come to know," but de Vaan reports this is "impossible," and with no attractive alternative explanation, it is of unknown origin.

Meaning "notice, attention" is from early 14c.; that of "reputation, fame" is from late 14c. From late 14c. as "mark, sign, or token by which a thing may be known." From late 14c. as "a sign by which a musical tone is represented to the eye." Meaning "a brief written abstract of facts" is from 1540s; meaning "a short, informal written communication" is from 1590s. From 1550s as "a mark in the margin of a book calling attention to something in the text," hence "a statement subsidiary to the text adding or elucidating something." From 1680s as "a paper acknowledging a debts, etc." In perfumery, "a basic component of a fragrance which gives it its character," by 1905.

Definitions of note
note (n.)
a brief written record;
he made a note of the appointment
note (n.)
a short personal letter;
Synonyms: short letter / line / billet
note (n.)
a notation representing the pitch and duration of a musical sound;
the singer held the note too long
Synonyms: musical note / tone
note (n.)
a tone of voice that shows what the speaker is feeling;
there was a note of uncertainty in his voice
note (n.)
a characteristic emotional quality;
it ended on a sour note
there was a note of gaiety in her manner
he detected a note of sarcasm
note (n.)
a piece of paper money (especially one issued by a central bank);
he peeled off five one-thousand-zloty notes
Synonyms: bill / government note / bank bill / banker's bill / bank note / banknote / Federal Reserve note / greenback
note (n.)
a comment or instruction (usually added);
his notes were appended at the end of the article
Synonyms: annotation / notation
note (n.)
high status importance owing to marked superiority;
Synonyms: eminence / distinction / preeminence
note (n.)
a promise to pay a specified amount on demand or at a certain time;
I had to co-sign his note at the bank
Synonyms: promissory note / note of hand
note (v.)
make mention of;
They noted that it was a fine day to go sailing
Synonyms: observe / mention / remark
note (v.)
notice or perceive;
She noted that someone was following her
Synonyms: notice / mark
note (v.)
observe with care or pay close attention to;
Take note of this chemical reaction
Synonyms: take note / observe
note (v.)
make a written note of;
she noted everything the teacher said that morning
Synonyms: take down