Simple Definition of alter
: to change (something)
: to make a change to (a piece of clothing) so that it will fit better
: to remove the sex organs of (an animal) so that the animal is unable to reproduce
Full Definition of alter
Examples of alter
Alcohol can alter a person's mood.
He altered his will to leave everything to his sister.
This one small event altered the course of history.
The place has altered in the 10 years since I left.
I'll need to have the dress altered before the wedding.
Origin of alter
Middle English, from Medieval Latin alterare, from Latin alter other (of two); akin to Latin alius other — more at else
First Known Use: 14th century
Synonym Discussion of alter
Seen and Heard
What made you want to look up alter? Please tell us where you read or heard it (including the quote, if possible).