note 
(nōt)
(nōt)n.
1.
a. A brief record, especially one written down to aid the memory: took notes on the lecture.
b. A comment or explanation, as on a passage in a text: The allusion is explained in the notes at the end of the chapter.
2.
a. A brief informal letter: sent a note to the child's teacher. See Synonyms at letter.
b. A formal written diplomatic or official communication.
3.
a. A piece of paper currency.
b. A debt security, usually with a maturity of ten years or less.
c. A promissory note.
4. Music
a. A tone of definite pitch.
b. A symbol for such a tone, indicating pitch by its position on the staff and duration by its shape.
c. A key of an instrument, such as a piano.
5. The characteristic vocal sound made by a songbird or other animal: the clear note of a cardinal.
6. The sign of a particular quality or emotion: a note of despair in his remarks; a note of gaiety in her manner.
7. A distinctive component of a complex flavor or aroma: a full-bodied wine with notes of cherry and musk.
8. Importance; consequence: Nothing of note happened.
9. Notice; observation: quietly took note of the scene.
10. Obsolete A song, melody, or tune.
tr.v. not·ed, not·ing, notes
1. To observe carefully; notice: Note the difference between these two plants. See Synonyms at see1.
2. To make a note of; write down: noted the time of each arrival.
3. To show; indicate: a reporter careful to note sources of information.
4. To make mention of; remark: noted the lateness of his arrival.
[Middle English, from Old French, from Latin nota, annotation; see gnō- in the Appendix of Indo-European roots.]
noter n.