That push, whether it's a reason, an event, or a moment, is called impetus.

Impetus refers to a force or reason that makes something happen or speeds it up, it could be a deadline, a conversation or even a setback.

Where it comes from

The word comes from the Latin word 'impetus', meaning "attack, force, or momentum," derived from impetere, meaning "to rush at."

In early scientific thought, impetus was used to explain why objects keep moving after being set in motion, long before modern physics defined momentum. Over time, the meaning shifted from a physical force to a more abstract one, the driving force behind actions, decisions, or change.

How it's used today

In modern English, impetus usually refers to something that triggers or accelerates action.

Here are a few examples:

• The new policy provided the impetus for educational reforms.

• Her decision to move cities became the impetus for a fresh start.

• The crisis acted as an impetus for long-overdue changes.

Impetus is widely used in journalism and policy writing, especially when explaining causes behind developments.

Unlike momentum, which suggests ongoing movement, impetus is often the initial push. The word still carries a sense of energy and urgency from its original meaning.