These terms have migrated across industries, and into regular life, but I first began using them and others as a teenage line cook at a busy restaurant. To be sure, the floor and bar staff use them as well, and I've found some of them to be nigh universal in commercial U.S. kitchens.

Spat: Spatula. As in, "I once saw him spit on his spat, man."

Working: Adjective applied to food to refer to its being in the process of being prepared. As in, "You got them nachos working yet?"

Nuke: To microwave. This one's very common now, but I'd never heard/used it before the kitchen those many years ago. As in, "I'll nuke the nachos."

Slammed: Very busy. As in, "I was already slammed when she ordered four deluxe burgers." The burgers will exacerbate the slam, since each will have to be cooked differently. Depending on the degree of the slam in progress, the burgers are likely to all end up medium.

In the weeds: Slammed and behind on orders. As in, "So right after I get the burgers working, she comes back with two cheese steaks and three fuh-jittas*, and man we're in the weeds." TheDeadGuy elsewhere defines in the weeds as a state of mind of being too busy to think straight, which I'll buy as this state of mind often results from being in the weeds.

Meltdown: When applied to food, this means it's at or approaching burnt, completely melted, or otherwise being rendered unfit for consumption. As in, "Dammit! Your nachos are melting down!" When applied to line cooks, it means total nervous failure due to being in the weeds too long. As in, "So then he has a meltdown, screams, 'Fuck it!,' slams his spat on the grill, clocks out, and leaves."

All day: Applied to a complete count of dishes outstanding, regardless of which order they belong to. As in, "Crap, two more. That's five fuh-jittas all day, people."

Alleged: This one may have been unique to my kitchen; but it's a good one. Applied to something you're supposed to be preparing, and implies doubt that you'll be able to produce it on time. As in, "You got those alleged cheese steaks working?" I still use this one in many contexts.

There are more I'm forgetting, I'm sure...but thankfully I've had fifteen years to forget the hot, hectic, and greasy life of the long-suffering line cook.

*Deliberate corruption of fajitas, pronounced with a hard J and short I. Cooks sometimes tend to corrupt the names of dishes, especially the loathed complex ones like these.