The word "note" describes something written, usually a small amount of information. Sometimes "note" is used for seeing or understanding.
In these sentences, "note" is a noun:
Good students take notes in class.
Solomon has a note from his doctor which explains why he missed so much work.
Sarah got in trouble for passing notes in class. (To pass notes is to send secret messages in writing. Children often do this during a class.)
Do you have the notes from yesterday’s meeting?
Emma received a note of thanks from her supervisor because she did such good work on a project.
Bill got a note from his boss saying he was fired.
In these sentences,"note" is a verb:
You should note everything that’s important to remember.
The doctor noted that the patient’s breathing was heavy.
If I see anything out of the ordinary, I’ll note it in the report.
If you use the word "note" as an adjective, it becomes "noted." In this case the meaning of the word changes a little bit to mean that someone or something is famous or well known:
A noted author visited a local bookstore to sign books.
Bill McKibben is a noted expert on the impact that global warming is having on our climate.
Several noted celebrities have their pictures up on the wall of this cafe.
We also use the word "note" for musical notation and pitch:
It’s hard to hit the high notes on a trumpet.
Is that a quarter note or an eighth note?
eighth notes
Note: Related to the word "note" is "notice." This is not the same word, but it is similar.
eighth notes