80 DICTIONARY OF AVIATION
dirigible 'dizidsa-bgl, (improperly) di'zidsa-bal adj.
1. capable of being directed or guided; steerable.
2. ef or concernd with dirigible balloons.
dirigible 'dizidsa-bal n. a dirigible balloon; a lightersthan^ air airship: as, a war *dingible.
discontinuity ,dis-kenti'nju-i-ti n. the quality or state of being discontinuous; want or failure of continuity; inter- rupted condition.
kinetic discontinuity, a discontinuity in the kind or in the course of motion.
physical discontinuity, discontinuity in the kind, of matter.
surface of discontinuity, the surface which separates the live stream from the dedswater in the rear of a body of imperfect streamline form in its course thru the air or other fluid.
disembark ,disam'ba:zk n, land from an airship; get out upon the ground, as at the end of a voyage.
disk disk n. [also spelt disci the highest portion of the thorax or elytra of an insect, seen from above; the central part of the wing.
dispatch-bag di'spaet$,b3eg n. a bag used in sending di- spatches or messages from a balloon to the earth.
dispatch-craft di'spaet$,k5a:ft n. pi. aircraft used for send- ing dispatches or messages.
displacement ^is'pz.ees-'mant n. the quantity or weight of fluid which is displaced by a solid body (as an airship) placed in it.
distance-piece 'distns,piis n. a spar or other piece, as of wood, which is inserted between two objects to separate them or keep them a certain distance apart.
diurnal ,dai'Bznl adj.
1. performd in or occupying one day; daily.
2. ef or belonging to the day as distinguisht from the night : the epposit of nocturnal.
dive daiv n. a sudden dart downward, as of an aircraft; a descent or plunge hed first; a heder: as, a spiral *dive, a winding *dive, a sweeping *dive.
high dive, a dive or steep quick descent made in a fly- ingsmachine from high up in the air.
low dive, a dive or steep quick descent made in a flyings machine from a low altitude above the earth.
spiral dive, see under spiral.
dive daiv intr. [past participle dived', preterit dived and, sometimes, dove\ dart suddenly downward; descend hed first precipitately.
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