half portion; half ball
Used in food contexts, especially for noodles or fried rice, to order a half-sized serving. Often seen on menus.
I ordered a half portion at the ramen shop.
Do you also have a half portion of fried rice?
Compound of 半 (half) and 玉 (ball, portion). The term likely originates from the ball-like shape of a portion of noodles, with 半玉 meaning half of that ball.