A kitchen knife (used for cooking), especially the typical Japanese knives like santoku or deba.
包丁でネギを薄く切いてください。
Please slice the green onion thinly with the kitchen knife.
新しい包丁を買ったので、早速魚をさばいてみた。
I bought a new kitchen knife, so I immediately tried filleting a fish.
料理人は包丁さばきがとても上手だ。
The chef is very skilled with a kitchen knife.
Archaic: can mean cooking or food (an older usage), rarely used in modern Japanese.
古文には『庖丁の道』といった表現が見られ、料理の技術を指していた。
In classical texts you see phrases like 'the way of the kitchen knife', referring to culinary skill.