What is momentum and how is it defined?

[icecomet]

Homework Statement

What is momentum? How do you find it?

Homework Equations

The Attempt at a Solution

I think that momentum is massxvelocity... but what is it? the definition? dictionary.com says that it is... theforce or speed of movement; impetus, as of a physical object or course of events...
but that isn't right because momentum isn't velocity and velocity is speed w/ direction... momentum is speed,direction and force combined... but what is momentum? the definition?

 

[wesDOT]

The quantity of motion which is found by multiplying mass by velocity.

To me its somewhat hard to define as its more of a concept with practical uses.