Subcategories:
— [noun] (66)
— [adjective] (30)
— [adverb] (2)
— [verb (transitive)] (4)
— mechanics (887)
— energy or power of doing work (172)
— electromagnetic radiation (4250)
— science of sound (214)
— solid state physics (142)
— atomic physics (731)
— atomic nucleus (593)
— quantum theory (322)
— relativity (47)