to eat: to take in food, and by extension to consume or use something up.
This is the ordinary word for eating, used all over the New Testament for taking a meal, sharing food, going hungry, or being filled. It is one half of a single verb "to eat": the present-tense forms come from one stem (the word behind "eats" and "eating"), and the past-tense and "to eat" forms come from this one ("ate," "to eat"). The two stems are not two different words but two parts of the same verb, the way English uses "go" and "went."
Most of the time it simply means eating food, and nothing more is meant. But the same plain word carries real weight when the meal itself matters: eating the Passover, eating the consecrated bread, sharing the bread and cup of the Lord's Supper, or the long discussion in John where Jesus speaks of eating the bread of life and even eating his flesh. The word does not change; the meal it names is what makes the moment heavy.
It also stretches, as eating words do in many languages, to mean consuming or using up. Fire "eats" what it burns, and in the visions of Revelation a scroll is eaten and bodies are devoured. These are not a separate word, just the everyday picture of eating pressed into service for destruction and for taking something fully into oneself.