(dated, derogatory) A fanatical advocate for the nuclear arms race.

(colour) A light orange colour.

A psychotherapeutic diagram presenting individuals as nodes (with the patient at the centre) connected by lines indicating their relationships.

Johnston Atoll is a small atoll in the Pacific Ocean. It is an unincorporated, unorganized territory of the United States.

(obsolete) The mechanics of atoms.

A monoclonal antibody used in the combination drug atoltivimab/maftivimab/odesivimab to treat Zaire ebolavirus.

(physics) The study of atoms and their motion.

an atomic clock which uses the 1.4 GHz transition in a hydrogen atom to measure time to within 0.45 nanoseconds over a span of 12 hours

plural of hydrogen maser atomic clock

A medication used to treat migraines.