236 DICTIONARY OF AVIATION
tion after sunset (or before sunrise) produced by the r
flection of sunlight from the upper air. compare gloamin
glooming, dusk. twilight-arc 'tumi-lait,a:zk n. same meaning as twiligh
curve. twilight- curve 'tioai-lait,k8:ev n. [also spelt twilighticun
the curv or arc, sometimes very sharply defined, censtitu
ing the visible part of the circular outline or boundary (
the projection of the earth's shadow upon the sky, luhic
rises in the east just after the sun has set and, as :
passes to the zenith and thence to the western horizoi
gradually cuts off the tunlighteglow ; the tu>ilight#arc. twilight-glow 'ttuai-lait,gloo n. the glow or luster of th
twilight. twisting-action 'tu)istirj,3ek$Dn n. an action of tunsting c
spirally turning. twisting-effect 'tunstirj-i,fekt n. an effect having the ns
ture of a tunst or spiral turn. two-bladed ,tuu'blee-did, (assumptivly) 'tuu,blee-did ad t
having two blades, as a screw propeller. two-winged ,tuu'wind, (assumptivly) 'tuu,wirjd adj. [als
spelt two*wingd\ having two wings or winglike sustaining
surfaces. tying-point 'tai-ir^pomt n. the point al which the guylin
or stjing of a kite is altacht, as to the hanger or bridle; th
tying^en peint. typhoon ,tai'foun n. [also spelt tyfoon] a violent hurncan
occurring in the China seas and thereabouts, mostly fron
July to October.
��unclouded ,An'ktao-did adj. net clouded : as, an *unclouded
but misty, sky. underbody 'Andazjbedi n. the bedy or framework fermins
the under part of an airship; the rigid underst^ucture at
tacht or suspended beneath the float^vessel ; the fuselage. underplane 'And9z,pi.een n. a stationary plane situated jus
under a moving or soaring plane; a plane surface, such a
a level piece of land or a water^surface, lying close be
neath an aeroplane or flyer, in flight. underrun ,And9'zAn tr. run or pass under or underneath
as, the thunder^squall *underruns humid air^currents. understructnre 'And3z,stjAkt$3z n. a structure unde
another; the lower part or parts of an airship, underneatl
the gasbag; the underbody; the underwork.
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