物理(wù lǐ) - physics in Mandarin

物理 (wùlǐ) is physics, the school and university subject. It comes from 物 (wù), "thing, matter", and 理 (lǐ), "principle, reason", so the compound reads as "the principles of matter", a fairly transparent name for the subject once you know the two pieces.

As a school subject it sits alongside 化学 (huàxué), "chemistry", and 生物 (shēngwù), "biology", the three sciences that make up 理科 (lǐkē), "the sciences" as a curriculum stream, contrasted with 文科 (wénkē), "the humanities". 物理课 (wùlǐkè) is "physics class" and 物理老师 (wùlǐ lǎoshī) is "physics teacher".

Outside the classroom, 物理 (wùlǐ) also appears as an adjective meaning "physical" in a technical sense, as in 物理治疗 (wùlǐ zhìliáo), "physiotherapy" (literally "physical treatment"). That broader use is worth flagging, since learners tend to only associate the word with the school subject.