noun
whitebait; young sardines
Refers to the juvenile stage of sardines, anchovies, or similar small fish, often eaten whole. In Japanese cuisine, シラス is typically boiled and served over rice or used in various dishes.
朝ごはんにシラスをご飯にかけて食べた。
I had whitebait over rice for breakfast.
noun
elver; young eel
Less common usage; specifically refers to young eels. In contexts where the type of fish is clear, シラス can mean elvers, but usually it implies whitebait.
この地域では、シラスと言えばウナギの稚魚を指すこともある。
In this region, 'shirasu' can sometimes refer to young eels.
The origin is uncertain. The word しらす likely derives from 白 (しら, white) + す (a suffix or particle), referring to the pale, translucent appearance of the young fish.