Rainbow vs. Spectrum — What's the Difference?

A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc.

A spectrum (plural spectra or spectrums) is a condition that is not limited to a specific set of values but can vary, without steps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors in visible light after passing through a prism.

An arc of spectral colors, usually identified as red, orange, yellow, green, blue, indigo, and violet, that appears in the sky opposite the sun as a result of the refractive dispersion of sunlight in drops of rain or mist.

The entire range over which some measurable property of a physical system or phenomenon can vary, such as the frequency of sound, the wavelength of electromagnetic radiation, or the mass of specific kinds of particles.

A similar arc or band, as one produced by a prism or by iridescence.

A specific portion of such a range

A graded display of colors.

A characteristic distribution of phenomena manifested over such a range

An illusory hope

A graphic representation of such a distribution; a spectrogram.

A diverse assortment or collection.

A band of colors produced when the wavelengths making up white light are separated, as when light passes through a prism or strikes drops of water.

A multicoloured arch in the sky, produced by prismatic refraction of light within droplets of rain in the air.

A range of radio frequencies assigned by a regulatory agency for use by a given group or organization.

Any prismatic refraction of light showing a spectrum of colours.

A range of values of a quantity or set of related quantities

(often used with “of”) A wide assortment; a varied multitude.

A sequence or range of related qualities, ideas, activities, entities, or phenomena

(figurative) An illusion; a mirage.

A range; a continuous, infinite, one-dimensional set, possibly bounded by extremes.

(baseball) A curveball, particularly a slow one.

Specifically, a range of colours representing light (electromagnetic radiation) of contiguous frequencies; hence electromagnetic spectrum, visible spectrum, ultraviolet spectrum, etc.

(poker slang) In Texas hold 'em or Omaha hold 'em, a flop that contains three different suits.

The autism spectrum.

A person within the LGBT community.

(chemistry) The pattern of absorption or emission of radiation produced by a substance when subjected to energy (radiation, heat, electricity, etc.).

Made up of several races or ethnicities, or (more broadly) of several cultural or ideological factions.

The set of eigenvalues of a matrix.

(attributive) LGBT.

Of a bounded linear operator A, the set of scalar values λ such that the operator A—λI, where I denotes the identity operator, does not have a bounded inverse; intended as a generalisation of the linear algebra sense.

Composed entirely of different suits.

The set, denoted Spec(R), of all prime ideals of a given ring R, commonly augmented with a Zariski topology and considered as a topological space.

Of or pertaining to rainbow tables.

(obsolete) Specter, apparition.

(transitive) To brighten with, or as with, a rainbow; to pattern with the colours of the rainbow.

The image of something seen that persists after the eyes are closed.

(intransitive) To take the appearance of a rainbow.

An apparition; a specter.

(climbing) In climbing gyms where the rocks to climb are colored to indicate suggested climbing routes, to climb rocks of different colors, thereby ignoring such routes.

The several colored and other rays of which light is composed, separated by the refraction of a prism or other means, and observed or studied either as spread out on a screen, by direct vision, by photography, or otherwise. See Illust. of Light, and Spectroscope.

A bow or arch exhibiting, in concentric bands, the several colors of the spectrum, and formed in the part of the hemisphere opposite to the sun by the refraction and reflection of the sun's rays in drops of falling rain.

An ordered array of the components of an emission or wave

An arc of colored light in the sky caused by refraction of the sun's rays by rain

Broad range of related values or qualities or ideas or activities

An illusory hope;