The term you’re looking for is “harvest festival.”

Quick Scoop

In many countries, the annual celebration that happens once the crops have been gathered is called a harvest festival.

It’s usually held in late summer or autumn, when the main harvest of the region is finished.

What is a harvest festival?

  • It is an annual celebration that takes place around the time of the main harvest in a region.
  • People traditionally give thanks for a successful harvest and for having enough food for the coming months.
  • These celebrations appear in many cultures worldwide, though each has its own name and customs.

Common features

  • Feasting with foods made from the freshly gathered crops.
  • Music, dancing, and games , often as a break after long months of work in the fields.
  • Thanksgiving or gratitude rituals , sometimes religious (church services, prayers, offerings).

Different names, same idea

  • In the UK and some English-speaking countries, it’s literally called Harvest Festival or Harvest Thanksgiving.
  • In the United States, Thanksgiving is essentially a type of harvest festival.
  • Other cultures have their own harvest festivals, such as Irreecha in Ethiopia or autumn moon/harvest celebrations in East Asia.

So if the question is: “What is the term for the annual celebration that occurs in many countries when the crops have been gathered?”
The standard answer is: harvest festival.

TL;DR: The annual celebration in many countries after crops are gathered is called a harvest festival.

Information gathered from public forums or data available on the internet and portrayed here.