A ray is a beam of light or radiation. Even on cloudy days, you sometimes see a ray of sunlight shine through the clouds.

In physics, a ray is a line or column of light, heat, or electromagnetic radiation (like an x-ray), while in math a ray is a line that passes through a specific point. A marine biologist would define a ray as a big fish that's related to sharks and has a wide, flat body and a long tail. The root of the first two kinds of rays is the Latin word radius, "spoke" or "staff."

Primary Meanings of ray

a group of nearly parallel lines of electromagnetic radiation
emit as rays
a branch of an umbel or an umbelliform inflorescence
the syllable naming the second (supertonic) note of any major scale in solmization
any of the stiff bony spines in the fin of a fish
Full Definitions of ray

n a group of nearly parallel lines of electromagnetic radiation

beam, electron beam
cathode ray
a beam of electrons emitted by the cathode of an electrical discharge tube
particle beam
a collimated flow of particles (atoms or electrons or molecules)
ion beam, ionic beam
a beam of ions moving in the same direction at the same speed
Type of:
electromagnetic radiation, electromagnetic wave, nonparticulate radiation
radiation consisting of waves of energy associated with electric and magnetic fields resulting from the acceleration of an electric charge

n a column of light (as from a beacon)

beam, beam of light, irradiation, light beam, ray of light, shaft, shaft of light
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heat ray
a ray that produces a thermal effect
high beam
the beam of a car's headlights that provides distant illumination
moon ray, moon-ray, moonbeam
a ray of moonlight
sunbeam, sunray
a ray of sunlight
laser beam
a beam of light generated by a laser
low beam
the beam of a car's headlights that provides illumination for a short distance
infrared ray
a ray of infrared radiation; produces a thermal effect (as from an infrared lamp)
Type of:
light, visible light, visible radiation
(physics) electromagnetic radiation that can produce a visual sensation

n (mathematics) a straight line extending from a point

Type of:
a straight line segment whose length is magnitude and whose orientation in space is direction

v emit as rays

“That tower rays a laser beam for miles across the sky”
Type of:
emit, give off, give out
give off, send forth, or discharge; as of light, heat, or radiation, vapor, etc.

v extend or spread outward from a center or focus or inward towards a center

Type of:
extend, go, lead, pass, run
stretch out over a distance, space, time, or scope; run or extend between two points or beyond a certain point

v expose to radiation

direct high energy particles or radiation against
Type of:
process, treat
subject to a process or treatment, with the aim of readying for some purpose, improving, or remedying a condition

n a branch of an umbel or an umbelliform inflorescence

Type of:
pedicel, pedicle
a small stalk bearing a single flower of an inflorescence; an ultimate division of a common peduncle

n the syllable naming the second (supertonic) note of any major scale in solmization

Type of:
solfa syllable
one of the names for notes of a musical scale in solmization

n any of the stiff bony spines in the fin of a fish

Type of:
a sharp rigid animal process or appendage; as a porcupine quill or a ridge on a bone or a ray of a fish fin

n cartilaginous fishes having horizontally flattened bodies and enlarged winglike pectoral fins with gills on the underside; most swim by moving the pectoral fins

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crampfish, electric ray, numbfish, torpedo
any sluggish bottom-dwelling ray of the order Torpediniformes having a rounded body and electric organs on each side of the head capable of emitting strong electric discharges
primitive ray with sharp teeth on each edge of a long flattened snout
primitive tropical bottom-dwelling ray with a guitar-shaped body
large venomous ray with large barbed spines near the base of a thin whiplike tail capable of inflicting severe wounds
eagle ray
powerful free-swimming tropical ray noted for `soaring' by flapping winglike fins; usually harmless but has venomous tissue near base of the tail as in stingrays
devilfish, manta, manta ray
extremely large pelagic tropical ray that feeds on plankton and small fishes; usually harmless but its size make it dangerous if harpooned
large edible rays having a long snout and thick tail with pectoral fins continuous with the head; swim by undulating the edges of the pectoral fins
Pristis pectinatus, smalltooth sawfish
commonly found in tropical bays and estuaries; not aggressive
Dasyatis centroura, roughtail stingray
one of the largest stingrays; found from Cape Cod to Cape Hatteras
butterfly ray
a stingray with a short tail and a broad fin
Aetobatus narinari, spotted eagle ray, spotted ray
ray with back covered with white or yellow spots; widely distributed in warm seas
Rhinoptera bonasus, cow-nosed ray, cownose ray
large ray found along eastern coast of North America
Atlantic manta, Manta birostris
largest manta (to 22 feet across wings); found worldwide but common in Gulf of Mexico and along southern coasts of United States; primarily oceanic
Mobula hypostoma, devil ray
small manta (to 4 feet) that travels in schools
Raja batis, gray skate, grey skate
common European skate used as food
Raja erinacea, little skate
most plentiful skate in North American inshore waters in summer; to 21 inches
Raja radiata, thorny skate
cold-water bottom fish with spines on the back; to 40 inches
Raja laevis, barndoor skate
one of the largest skates (to 5 feet); an active skate easy to hook
Type of:
elasmobranch, selachian
any of numerous fishes of the class Chondrichthyes characterized by a cartilaginous skeleton and placoid scales: sharks; rays; skates

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