momentum

The word “momentum” means in physics, a measure of a moving object's motion, calculated as its mass multiplied by its velocity. In plain terms, the force or drive behind movement or progress — literal in physics, figurative in everyday use.

“Momentum” is pronounced muh-MEHN-tuhm (/ˌmoʊˈmɛntəm/ in IPA).

Here is “momentum” used in a sentence: “The truck's momentum made it impossible to stop quickly.”

“Momentum” is a noun.

The word “momentum” comes from Latin. Borrowed directly from Latin mōmentum, "movement, moving power" — the same root that gives us "moment.".

“Momentum” is a fairly common word in modern English.

“Momentum” has 2 distinct senses listed in this dictionary. The most common is: in physics, a measure of a moving object's motion, calculated as its mass multiplied by its velocity.

Velocity is an object's speed in a given direction, while momentum is the object's mass multiplied by its velocity. That mass factor is the key difference: a truck and a bicycle traveling at the same velocity have hugely different momentum.

Inertia is an object's resistance to any change in its motion and depends only on its mass, whereas momentum is the quantity of motion the object actually has, equal to mass times velocity. A parked car has inertia but zero momentum.

In physics, the usual plural is momenta, though momentums is also acceptable. In the figurative "driving force" sense, the word is treated as uncountable, so no plural is normally needed.