n (grammar) A punctuation mark used to indicate the end of a sentence or an abbreviation|abbreviated part of a word; a full stop; a period.
n A diacritical mark comprised of a dot above or below any of various letters of the Latin script. Examples include: Ȧ, Ạ, Ḅ, Ḃ, Ċ, etc.
n (mathematics) A symbol used for separating the fractional part of a decimal number from the whole part, for indicating multiplication or a scalar product, or for various other purposes.