(astronomy, meteorology, geology) The portion of the flight of a meteor, after its incandescent fireball phase, when the space rock has cooled down and slowed down, so that it is no longer glowing, but still in flight, and yet to crash onto the ground.

(astronomy, cosmology) A linked phenomenon conjectured to explain dark matter and dark energy as different manifestations of the same underlying laws of gravity.

(psychology) An effect observed in fighter aircraft pilots, where horizontal acceleration at more than 1 standard gravity causes extreme stimulation of the vestibular system and leads to the faulty perception that the aircraft is climbing.

(physics) A state of hydrogen that is poorly electrically conductive (much less conductive than metallic hydrogen).

Alternative letter-case form of Darwinism.

(intransitive, originally, now less common) Alternative form of daresay

Alternative form of dark fibre

Unused optical fibre that is available for use

Data that are unanalyzed, inaccessible, or not organised in such a way that they are readily available.

plural of act of darkness