[ par-uh-lel, -luhl ]
See synonyms for: parallelparalleledparallelingparallels on

  1. extending in the same direction, equidistant at all points, and never converging or diverging: Parallel rows of trees lined two ends of the parking lot.

  2. having the same direction, course, nature, or tendency; corresponding; similar; analogous: Canada and the United States have many parallel economic interests.

  1. Geometry.

    • (of straight lines) lying in the same plane but never meeting no matter how far extended.

    • (of planes) having common perpendiculars.

    • (of a single line, plane, etc.) equidistant from another or others (usually followed by to or with).

  2. Electricity. consisting of or having component parts connected in such a way that all positive terminals are connected to one point and all negative terminals are connected to a second point, the same voltage being applied to each component: a parallel circuit.

  3. Music.

    • (of two voice parts) progressing so that the interval between them remains the same.

    • (of a tonality or key) having the same tonic but differing in mode: A major and A minor are parallel keys.

  4. Computers.

    • of or relating to the apparent or actual performance of more than one operation at a time by the same or different devices (distinguished from serial): Some computer systems join more than one CPU for parallel processing.

    • of or relating to the simultaneous transmission or processing of all the parts of a whole, as all the bits of a byte or all the bytes of a computer word (distinguished from serial).

  5. Grammar. consisting of matched syntactic elements in corresponding positions: In the sentence “I have three cats and two dogs,” “three cats” and “two dogs” are in parallel structure.

  1. a parallel line or plane.

  2. anything parallel or comparable to something else in direction, course, nature, or tendency.

  1. Also called parallel of latitude. Geography.

    • an imaginary circle on the earth's surface formed by the intersection of a plane parallel to the plane of the equator, bearing east and west and designated in degrees of latitude north or south of the equator along the arc of any meridian.

    • the line representing this circle on a chart or map.

  2. something identical or similar in essential respects; match; counterpart: It's a struggle to diagnose a case history without a known parallel.

  3. correspondence or analogy: These two cases have some parallel with each other.

  4. a comparison of things as if regarded side by side.

  5. Electricity. an arrangement of the components, such as resistors, of a circuit in such a way that all positive terminals are connected to one point and all negative terminals are connected to a second point, the same voltage being applied to each component.: Compare series (def. 9).

  6. Fortification. a trench cut in the ground before a fortress, parallel to its defenses, for the purpose of covering a besieging force.

  7. Printing. a pair of vertical parallel lines (‖) used as a mark for reference.

  8. Theater. a trestle for supporting a platform (parallel top ).

verb (used with object),par·al·leled, par·al·lel·ing or (especially British) par·al·lelled, par·al·lel·ling.
  1. to provide or show a parallel for; match.

  2. to go or be in a parallel course, direction, etc., to: The road parallels the river.

  1. to form a parallel to; be equivalent to; equal.

  2. to show the identity or similarity of; compare.

  3. to make parallel.

Idioms about parallel

  1. in parallel,

    • at the same time or in conjunction: When you are at school, your growth and change is taking place in parallel with fellow students who are also growing and changing.

    • Electricity. (of the components of a circuit) arranged in such a way that all positive terminals are connected to one point and all negative terminals are connected to a second point, the same voltage being applied to each component.

Origin of parallel

First recorded in 1540–50; from Latin parallēlus, from Greek parállēlos “side by side,” from par- par- + állēlos “one another” (see allo-)

Other words for parallel

Opposites for parallel

Other words from parallel

  • par·al·lel·a·ble, adjective
  • par·al·lel·less, adjective
  • par·al·lel·ly, adverb
  • non·par·al·lel, adjective, noun
  • sub·par·al·lel, adjective
  • un·par·al·lel, adjective

Words Nearby parallel Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use parallel in a sentence

British Dictionary definitions for parallel


/ (ˈpærəˌlɛl) /

adjective(when postpositive, usually foll by to)
  1. separated by an equal distance at every point; never touching or intersecting: parallel walls

  2. corresponding; similar: parallel situations

  1. music

    • Also: consecutive (of two or more parts or melodies) moving in similar motion but keeping the same interval apart throughout: parallel fifths

    • denoting successive chords in which the individual notes move in parallel motion

  2. grammar denoting syntactic constructions in which the constituents of one construction correspond to those of the other

  3. computing operating on several items of information, instructions, etc, simultaneously: Compare serial (def. 6)

  1. maths one of a set of parallel lines, planes, etc

  2. an exact likeness

  1. a comparison

  2. Also called: parallel of latitude any of the imaginary lines around the earth parallel to the equator, designated by degrees of latitude ranging from 0° at the equator to 90° at the poles

    • a configuration of two or more electrical components connected between two points in a circuit so that the same voltage is applied to each (esp in the phrase in parallel)

    • (as modifier): a parallel circuit See series (def. 6)

  3. printing the character (∥) used as a reference mark

  4. a trench or line lying in advance of and parallel to other defensive positions

verb-lels, -leling or -leled (tr)
  1. to make parallel

  2. to supply a parallel to

  1. to be a parallel to or correspond with: your experience parallels mine

Origin of parallel

C16: via French and Latin from Greek parallēlos alongside one another, from para- 1 + allēlos one another

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for parallel


[ părə-lĕl′ ]

  1. Of or relating to lines or surfaces that are separated everywhere from each other by the same distance.

  1. Any of the imaginary lines encircling the Earth's surface parallel to the plane of the equator, used to represent degrees of latitude. See illustration at longitude.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.