(physics) An atomic nucleus whose radius is appreciably larger than that predicted by the liquid drop model (wherein the nucleus is assumed to be a sphere of constant density).

(astronomy, meteorology) an upper atmospheric optical phenomena associated with thunderstorms, diffuse disk shaped glows that precede sprites and propagate downward

(geology) A microscopic spherical region in which there is a change in colour from the surrounding mineral; due to radiation damage from alpha particles.

(psychology) A cognitive bias in which judgment of somebody's character is influenced by an overall impression of him or her.

(astronomy) An aggregation of individual stars, dust, and gas (and possibly dark matter) that surrounds a galaxy

(phytopathology) A bacterial disease of bean plants, caused by Pseudomonas syringae pv. phaseolicola.

plural of halo car

A flagship car model used to bring prestige to a mark or brand of autos, through the halo effect, by symbolic association with other car models and the brand itself.

plural of halo sign

(radiology) The finding of a dark halo around the arterial lumen on ultrasound, suggesting a diagnosis of temporal arteritis.