What is light?

  • (adj): Used of vowels or syllables; pronounced with little or no stress.
    Example: "A syllable that ends in a short vowel is a light syllable"
    Synonyms: unaccented, weak
    See also — Additional definitions below


Visible light (commonly referred to simply as light) is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has a wavelength in the range of about 380 nanometres to about 740 nm – between the invisible infrared, with longer wavelengths and the invisible ultraviolet, with shorter wavelengths.

Read more about Light.

Some articles on light:

Color Temperature - Color Rendering Index
... The CIE color rendering index (CRI) is a method to determine how well a light source's illumination of eight sample patches compares to the illumination provided by a reference source ... the CRI and CCT give a numerical estimate of what reference (ideal) light source best approximates a particular artificial light, and what the difference is ...
Historical Theories About Light, in Chronological Order - Electromagnetic Theory As Explanation For All Types of Visible Light and All EM Radiation
... that the plane of polarisation of linearly polarised light is rotated when the light rays travel along the magnetic field direction in the presence of a transparent dielectric, an effect now known as Faraday rotation ... This was the first evidence that light was related to electromagnetism ... In 1846 he speculated that light might be some form of disturbance propagating along magnetic field lines ...
Speed Of Gravity - Lorentz Covariant Models
... c would contradict the concept of local time (based on synchronization by light signals) and the principle of relativity ... What would happen if we could communicate by signals other than those of light, the velocity of propagation of which differed from that of light? If ... is transmitted with a velocity a million times as great as that of light? However, in 1905 Poincaré calculated that changes in the gravitational field can propagate with the speed of ...
Flash - Light
... source of very short and extremely bright flashes of light Arc flash, an electrical explosion Lightning, a natural phenomenon Muzzle flash, the visible light of the ...
Correlated Color Temperature - Motivation
... Black body radiators are the reference by which the whiteness of light sources is judged ... By analogy, nearly-Planckian light sources such as certain fluorescent or high-intensity discharge lamps can be judged by their correlated color temperature (CCT) the color temperature of the Planckian radiator ... The question is what is the relationship between the light source's relative spectral power distribution and its correlated color temperature? ...

More definitions of "light":

  • (adv): With few burdens.
    Example: "Experienced travellers travel light"
    Synonyms: lightly
  • (noun): (physics) electromagnetic radiation that can produce a visual sensation.
    Example: "The light was filtered through a soft glass window"
    Synonyms: visible light, visible radiation
  • (noun): An illuminated area.
    Example: "He stepped into the light"
  • (adj): Easily assimilated in the alimentary canal; not rich or heavily seasoned.
    Example: "A light diet"
  • (noun): A device for lighting or igniting fuel or charges or fires.
    Example: "Do you have a light?"
    Synonyms: lighter, igniter, ignitor
  • (adj): Having a spongy or flaky texture; well-leavened.
    Example: "Light pastries"
  • (noun): Public awareness.
    Example: "It brought the scandal to light"
  • (adj): Very thin and insubstantial.
    Example: "Light summer dresses"
    Synonyms: flimsy
  • (adj): Characterized by or emitting light.
    Example: "A room that is light when the shutters are open"; "the inside of the house was airy and light"
  • (noun): Any device serving as a source of illumination.
    Synonyms: light source
  • (adj): Intended primarily as entertainment; not serious or profound.
    Example: "Light verse"; "a light comedy"
  • (adj): Psychologically light; especially free from sadness or troubles.
    Example: "A light heart"
  • (noun): A condition of spiritual awareness; divine illumination.
    Example: "Follow God's light"
    Synonyms: illumination
  • (adj): Weak and likely to lose consciousness.
    Example: "Felt light in the head"; "light-headed with wine"; "light-headed from lack of sleep"
    Synonyms: faint, swooning, light-headed, lightheaded
  • (adj): (of sleep) easily disturbed.
    Example: "In a light doze"; "a light sleeper"
    Synonyms: wakeful
  • (verb): Fall to somebody by assignment or lot.
    Synonyms: fall
  • (adj): Less than the correct or legal or full amount often deliberately so.
    Example: "A light pound"
    Synonyms: scant, short
  • (verb): Cause to start burning; subject to fire or great heat.
    Example: "Light a cigarette"
    Synonyms: ignite
  • (adj): Of little intensity or power or force.
    Example: "The light touch of her fingers"; "a light breeze"
  • (adj): Demanding little effort; not burdensome.
    Example: "Light housework"; "light exercise"
  • (noun): A visual warning signal.
    Example: "They saw the light of the beacon"; "there was a light at every corner"
  • (noun): Brightness and animation of countenance.
    Synonyms: sparkle, spark
  • (noun): A particular perspective or aspect of a situation.
    Example: "Although he saw it in a different light, he still did not understand"
  • (adj): Not great in degree or quantity or number.
    Example: "A light sentence"; "a light accent"; "casualties were light"; "light snow was falling"; "light misty rain"; "light smoke from the chimney"
  • (noun): A person regarded very fondly.
    Example: "The light of my life"
  • (adj): (used of color) having a relatively small amount of coloring agent.
    Example: "Light blue"; "light colors such as pastels"; "a light-colored powder"
    Synonyms: light-colored
  • (adj): Of the military or industry; using (or being) relatively small or light arms or equipment.
    Example: "Light infantry"; "light cavalry"; "light industry"; "light weapons"
  • (adj): Having relatively few calories.
    Example: "Light (or lite) beer"
    Synonyms: lite, low-cal
  • (adj): (physics, chemistry) not having atomic weight greater than average.
    Example: "Light water is ordinary water"
  • (adj): Of comparatively little physical weight or density.
    Example: "A light load"; "magnesium is a light metal--having a specific gravity of 1.74 at 20 degrees C"
  • (noun): Having abundant light or illumination.
    Example: "They played as long as it was light"
    Synonyms: lighting
  • (adj): Moving easily and quickly; nimble.
    Example: "The dancer was light and graceful"; "walked with a light tripping step"
    Synonyms: lightsome, tripping
  • (adj): (used of soil) loose and large-grained in consistency.
    Example: "Light sandy soil"
    Synonyms: friable, sandy
  • (verb): To come to rest, settle.
    Synonyms: alight, perch
  • (noun): Mental understanding as an enlightening experience.
    Example: "He finally saw the light"; "can you shed light on this problem?"
  • (adj): Marked by temperance in indulgence.
    Example: "A light eater"; "a light smoker"; "ate a light supper"
    Synonyms: abstemious
  • (adj): (of sound or color) free from anything that dulls or dims.
    Example: "A light lilting voice like a silver bell"
    Synonyms: clean, clear, unclouded
  • (adj): Designed for ease of movement or to carry little weight.
    Example: "Light aircraft"; "a light truck"
  • (adj): Having little importance.
    Example: "Losing his job was no light matter"
  • (adj): Silly or trivial.
    Example: "Light banter"; "light idle chatter"
    Synonyms: idle
  • (noun): The visual effect of illumination on objects or scenes as created in pictures.
    Example: "He could paint the lightest light and the darkest dark"
    Synonyms: lightness

Famous quotes containing the word light:

    But no. Too soon I voun’ my charm abroke.
    Noo comely soul in white like her—
    Noo soul a-steppen light like her—
    An’ nwone o’ comely height like her—
    Went by; but all my grief agean awoke.
    William Barnes (1801–1886)

    Dear friend,
    I will have to sink with hundreds of others
    on a dumbwaiter into hell.
    I will be a light thing.
    I will enter death
    like someone’s lost optical lens.
    Anne Sexton (1928–1974)

    “Lord, now lettest thou thy servant depart in peace, according to your word; for mine eyes have seen thy salvation, which thou hast prepared in the presence of all peoples, light for revelation to the Gentiles and for glory to thy people Israel.”
    Bible: New Testament (RSV)