羟 is a specialized chemistry character with no common everyday usage. It appears almost exclusively in scientific texts as part of 羟基 (qiǎngjī, hydroxyl group, -OH).
Left sheep radical 羊 - pictograph of a sheep's head with horns curving above. The indexing radical for 羟 by convention, though the sheep meaning is purely structural: modern chemistry borrowed 羟 to name the hydroxyl group (-OH) by phonetics. Same family: 美 beautiful, 群 flock.
Right five strokes - visually the simplified 圣, but historically a contracted form of 巠 jīng "underground stream / warp-thread." In modern chemistry 羟 was coined by phonetically blending 氢 (hydrogen) and 氧 (oxygen), giving the reading qiǎng.
