稀

A phono-semantic compound composed of:

禾 — semantic component meaning “grain; rice plant”;

希 — phonetic component indicating the sound (희 / xī). The character originally described grain plants growing sparsely, which led to the meaning rare or thinly scattered.
Semantic development: - sparse growth of plants; - rare or uncommon; - thin, diluted, or low density.

In many modern compounds, the character 希 is more commonly used than 稀.
희소 (希少) — rarity; scarce 희박 (希薄) — thin; rarefied; weak (density or concentration) 희토류 (希土類) — rare-earth elements

Related characters: 希 — rare; hope

少 — few; little

薄 — thin; weak 珍 — rare; precious
In Japanese, 稀 is listed as a name-use character (人名用漢字).