1. noun /ɡɹuːp/
a) A number of things or persons being in some relation to one another.
There is a group of houses behind the hill.
b) A set with an associative binary operation, under which there exists an identity element, and such that each element has an inverse.
A group of people gathered in front of the Parliament to demonstrate against the Prime Ministers proposals.
2. verb /ɡɹuːp/
a) To put together to form a group.
b) To come together to form a group.
Wikipedia foundation.