the branch of quantum physics that accounts for matter at the atomic level; an extension of statistical mechanics based on quantum theory (especially the Pauli exclusion principle)
English linguist who contributed to linguistic semantics and to prosodic phonology and who was noted for his insistence on studying both sound and meaning in context (1890-1960)
the time required for something to fall to half its initial value (in particular, the time for half the atoms in a radioactive substance to disintegrate)