N.

noun

A short piece of text, often numbered, placed at the bottom of a printed page, that adds a comment, citation, reference etc, to a designated part of the main text.
“consult the footnotes for more details”
(by extension) An event of lesser importance than some larger event to which it is related.
“a mere footnote in history”
A qualification to the import of something.

Neutral; on neither side; neither one thing nor another.
(grammar) Having a form which is not masculine nor feminine; or having a form which is not of common gender.
“a neuter noun”
(grammar) Intransitive.
“a neuter verb”

One of the four major compass points, specifically 0°, directed toward the North Pole, and conventionally upwards on a map, abbreviated as N.
“Minnesota is in the north of the USA.”
The up or positive direction.
“Stock prices are heading north.”
The positive or north pole of a magnet, which seeks the magnetic pole near Earth's geographic North Pole (which, for its magnetic properties, is a south pole).

Of, facing, situated in, or related to the north;northerly.
(of a wind) Blowing from the north; northerly.
Characteristic of the North of England (usually capitalised)
“Les Dawson was a famous northern comedian.”

That which is needed or necessary; business; duty; work.
The giving of milk by a cow or sow; the period following calving or farrowing during which a cow or sow is at her most useful (i.e. gives milk); the milk given by a cow or sow during such a period.

(grammar, narrow sense) A word that can be used to refer to a person, animal, place, thing, phenomenon, substance, quality, or idea; one of the basic parts of speech in many languages, including English.
(grammar, now rare, broad sense) Either a word that can be used to refer to a person, animal, place, thing, phenomenon, substance, quality or idea, or a word that modifies or describes a previous word or its referent; a substantive or adjective, sometimes also including other parts of speech such as numeral or pronoun.