Light (lt), n. [OE. light, liht, AS. leóht; akin to OS. lioht, D. & G.
licht, OHG. lioht, Goth. liuhaþ, Icel. ljs, L. lux light, lucere to
shine, Gr. leyko`s white, Skr. ruc to shine. √122. Cf. Lucid,
Lunar, Luminous, Lynx.] 1. That agent, force, or action in nature by
the operation of which upon the organs of sight, objects are rendered
visible or luminous.
Light was regarded formerly as consisting of material particles, or
corpuscules, sent off in all directions from luminous bodies, and
traversing space, in right lines, with the known velocity of about
186,300 miles per second; but it is now generally understood to
consist, not in any actual transmission of particles or substance, but
in the propagation of vibrations or undulations in a subtile, elastic
medium, or ether, assumed to pervade all space, and to be thus set in
vibratory motion by the action of luminous bodies, as the atmosphere is
by sonorous bodies. This view of the nature of light is known as the
undulatory or wave theory; the other, advocated by Newton (but long
since abandoned), as the corpuscular, emission, or Newtonian theory. A
more recent theory makes light to consist in electrical oscillations,
and is known as the electro-magnetic theory of light.
2. That which furnishes, or is a source of, light, as the sun, a star,
a candle, a lighthouse, etc.
Then he called for a light, and sprang in.
Acts xvi. 29.
And God made two great lights; the greater light to rule the day,
and the lesser light to rule the night.
Gen. i. 16.
3. The time during which the light of the sun is visible; day;
especially, the dawn of day.
The murderer, rising with the light, killeth the poor and needy.
Job xxiv. 14.