Here's the breakdown:
* Gills: These are the organs fish use to breathe underwater. They're located on the sides of their head.
* Stuffed: This means to fill something tightly, often with food.
* Metaphor: The phrase equates the fullness of a person's stomach to the fullness of a fish's gills after it's been stuffed with food.
Origin of the phrase:
The exact origin of the phrase is unknown, but it's been used in English for centuries. The earliest recorded use was in 1869, but it likely predates that.
Meaning:
"Stuffed to the gills" is used to describe someone who has eaten a lot of food and is feeling very full, almost to the point of discomfort.
Example:
"I ate so much at the buffet, I'm stuffed to the gills!"