Tempura usually consists of seafood and vegetables.
The pairing is central to the standard definition of tempura: ingredients such as shrimp, squid, fish, eggplant, sweet potato, lotus root, mushrooms, and peppers are dipped in a thin batter and briefly deep-fried. Vegetable tempura can be served as an entirely vegetarian dish and is sometimes called yasai tempura.
Tempura is not defined by one specific ingredient. Seafood is especially associated with the dish, but seasonal vegetables are equally important in Japanese cooking. Eggs can be part of the batter, yet they are not the broad ingredient group paired with seafood in the definition. Rice and noodles are more often accompaniments or bases for dishes that include tempura, such as tendon, tempura udon, and tempura soba.
The batter is traditionally kept cold and mixed minimally, often with chopsticks, to avoid developing too much gluten. That technique produces tempura’s characteristic pale, airy crispness rather than a heavy, breaded crust.