In physics, momentum refers to the mass of a moving object multiplied by its speed in a given direction. If we talk about a process or thing gaining momentum, it means it develops or evolves and is unlikely to slow down or stop. The momentum of something can refer to the driving force propelling something or forcing it to move.

1. The team's recent run of victories have helped them to create some momentum going into the critical part of the season.
2. The movie started off brilliantly, but by the end had lost all its momentum.
3. Henry's bike quickly gathered momentum as he coasted down the steep hill.

1. The hype around the product has been gaining momentum ever since we released our new advertising campaign.
2. Changes made to the business have been slow so far, but they should start gathering momentum by early next year.