A distinguishing feature of a person or thing.
For a given field or ring, a natural number that is either the smallest positive number n such that n instances of the multiplicative identity (1) summed together yield the additive identity (0) or, if no such number exists, the number 0.
The integer part of a logarithm.
The distinguishing features of a navigational light on a lighthouse etc by which it can be identified (colour, pattern of flashes etc.).
Being a distinguishing feature of a person or thing.
A person’s or thing’s first appearance before society or another audience; one’s “maiden voyage”.
To make one's début.