noun
soy sauce dish
A small shallow dish for holding soy sauce, typically used when eating sushi or sashimi.
寿司を食べるときは、醤油皿に醤油を入れてください。
When eating sushi, please pour soy sauce into the soy sauce dish.
取り皿 is a general small plate for taking food, while 醤油皿 is specifically for soy sauce.
Compound of 醤油 (しょうゆ, 'soy sauce') and 皿 (さら, 'dish'), with rendaku voicing さら → ざら.