Pastrami is beef that has been salted, smoked, and rubbed with a lot of spices — black pepper, garlic, coriander, that kind of thing — so the outside is dark and the inside stays pink and tender. It is Jewish deli food that became famous in New York; you usually eat it hot, in a thick sandwich, often with mustard and pickles, on rye bread. It is everyday American food talk, not a formal word. People stretch it a little: a menu may say “pastrami salmon,” meaning the same spice-and-smoke treatment on fish, though old deli cooks may not love that. Though actually, it sits next to corned beef in the same shops. Corned beef is salted beef; pastrami is the smoky, pepper-crusted one. They are cousins, not the same plate.