See more synonyms for sound on
adjective, sound·er, sound·est.
  1. free from injury, damage, defect, disease, etc.; in good condition; healthy; robust: a sound heart; a sound mind.
  2. financially strong, secure, or reliable: a sound business; sound investments.
  3. competent, sensible, or valid: sound judgment.
  4. having no defect as to truth, justice, wisdom, or reason: sound advice.
  5. of substantial or enduring character: sound moral values.
  6. following in a systematic pattern without any apparent defect in logic: sound reasoning.
  7. uninterrupted and untroubled; deep: sound sleep.
  8. vigorous, thorough, or severe: a sound thrashing.
  9. free from moral defect or weakness; upright, honest, or good; honorable; loyal.
  10. having no legal defect: a sound title to property.
  11. theologically correct or orthodox, as doctrines or a theologian.
  1. deeply; thoroughly: sound asleep.

Origin of sound

1150–1200; Middle English sund, Old English gesund (see y-); cognate with Dutch gezond, German gesund
Related formssound·ly, adverbsound·ness, noun

Synonyms for sound

See more synonyms for on Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for soundness

Contemporary Examples of soundness

Historical Examples of soundness

  • The experience of every day only proves the truth and soundness of your views.

    Vivian Grey

    Earl of Beaconsfield, Benjamin Disraeli

  • It had sunk into the heavy slumber of weariness, the soundness of peasants' sleep.

  • Hippias and Prodicus, as well as Protagoras, admit the soundness of the conclusion.

  • For soundness of foot a thick horn is far better than a thin.

  • The matter was to be settled not by force but by weight of numbers and soundness of title.

    The Fathers of New England

    Charles M. Andrews

British Dictionary definitions for soundness


    1. a periodic disturbance in the pressure or density of a fluid or in the elastic strain of a solid, produced by a vibrating object. It has a velocity in air at sea level at 0°C of 331 metres per second (741 miles per hour) and travels as longitudinal waves
    2. (as modifier)a sound wave
  1. (modifier) of or relating to radio as distinguished from televisionsound broadcasting; sound radio
  2. the sensation produced by such a periodic disturbance in the organs of hearing
  3. anything that can be heard
  4. a particular instance, quality, or type of soundthe sound of running water
  5. volume or quality of sounda radio with poor sound
  6. the area or distance over which something can be heardto be born within the sound of Big Ben
  7. the impression or implication of somethingI don't like the sound of that
  8. phonetics the auditory effect produced by a specific articulation or set of related articulations
  9. (often plural) slang music, esp rock, jazz, or pop
  1. to cause (something, such as an instrument) to make a sound or (of an instrument, etc) to emit a sound
  2. to announce or be announced by a soundto sound the alarm
  3. (intr) (of a sound) to be heard
  4. (intr) to resonate with a certain quality or intensityto sound loud
  5. (copula) to give the impression of being as specified when read, heard, etcto sound reasonable
  6. (tr) to pronounce distinctly or audiblyto sound one's consonants
  7. (intr usually foll by in) law to have the essential quality or nature (of)an action sounding in damages
See also sound off
Derived Formssoundable, adjective

Word Origin for sound

C13: from Old French soner to make a sound, from Latin sonāre, from sonus a sound


  1. free from damage, injury, decay, etc
  2. firm; solid; substantiala sound basis
  3. financially safe or stablea sound investment
  4. showing good judgment or reasoning; sensible; wisesound advice
  5. valid, logical, or justifiablea sound argument
  6. holding approved beliefs; ethically correct; upright; honest
  7. (of sleep) deep; peaceful; unbroken
  8. thorough; completea sound examination
  9. British informal excellent
  10. law (of a title, etc) free from defect; legally valid
  11. constituting a valid and justifiable application of correct principles; orthodoxsound theology
  12. logic
    1. (of a deductive argument) valid
    2. (of an inductive argument) according with whatever principles ensure the high probability of the truth of the conclusion given the truth of the premises
    3. another word for consistent (def. 5b)
  1. soundly; deeply: now archaic except when applied to sleep
Derived Formssoundly, adverbsoundness, noun

Word Origin for sound

Old English sund; related to Old Saxon gisund, Old High German gisunt


  1. to measure the depth of (a well, the sea, etc) by lowering a plumb line, by sonar, etc
  2. to seek to discover (someone's views, etc), as by questioning
  3. (intr) (of a whale, etc) to dive downwards swiftly and deeply
  4. med
    1. to probe or explore (a bodily cavity or passage) by means of a sound
    2. to examine (a patient) by means of percussion and auscultation
  1. med an instrument for insertion into a bodily cavity or passage to dilate strictures, dislodge foreign material, etc
See also sound out

Word Origin for sound

C14: from Old French sonder, from sonde sounding line, probably of Germanic origin; related to Old English sundgyrd sounding pole, Old Norse sund strait, sound 4; see swim


  1. a relatively narrow channel between two larger areas of sea or between an island and the mainland
  2. an inlet or deep bay of the sea
  3. the air bladder of a fish

Word Origin for sound

Old English sund swimming, narrow sea; related to Middle Low German sunt strait; see sound ³


  1. the Sound a strait between SW Sweden and Zealand (Denmark), linking the Kattegat with the Baltic: busy shipping lane; spanned by a bridge in 2000. Length of the strait: 113 km (70 miles). Narrowest point: 5 km (3 miles)Danish name: Øresund Swedish name: Öresund
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

Word Origin and History for soundness

late 14c., from sound (adj.) + -ness.



"noise, what is heard, sensation produced through the ear," late 13c., soun, from Old French son "sound, musical note, voice," from Latin sonus "sound, a noise," from PIE *swon-o-, from root *swen- "to sound" (cf. Sanskrit svanati "it sounds," svanah "sound, tone;" Latin sonare "to sound;" Old Irish senim "the playing of an instrument;" Old English geswin "music, song," swinsian "to sing;" Old Norse svanr, Old English swan "swan," properly "the sounding bird").

The terminal -d was established c.1350-1550 as part of a tendency to add -d- after -n-. First record of sound barrier is from 1939. Sound check is from 1977; sound effects is 1909, originally live accompaniments to silent films.

The experts of Victor ... will ... arrange for the synchronized orchestration and sound effects for this picture, in which airplane battles will have an important part. ["Exhibitor's Herald & Moving Picture World," April 28, 1928]



"free from special defect or injury," c.1200, from Old English gesund "sound, safe, having the organs and faculties complete and in perfect action," from Proto-Germanic *sunda-, from Germanic root *swen-to- "healthy, strong" (cf. Old Saxon gisund, Old Frisian sund, Dutch gezond, Old High German gisunt, German gesund "healthy," as in the post-sneezing interjection gesundheit; also Old English swið "strong," Gothic swinþs "strong," German geschwind "fast, quick"), with connections in Indo-Iranian and Balto-Slavic. Meaning "right, correct, free from error" is from mid-15c. Meaning "financially solid or safe" is attested from c.1600; of sleep, "undisturbed," from 1540s. Sense of "holding accepted opinions" is from 1520s.



"fathom, probe, measure the depth of," mid-14c. (implied in sounding), from Old French sonder, from sonde "sounding line," perhaps from the same Germanic source that yielded Old English sund "water, sea" (see sound (n.2)). Barnhart dismisses the old theory that it is from Latin subundare. Figurative use from 1570s.



"narrow channel of water," c.1300, from Old Norse sund "a strait, swimming," or from cognate Old English sund "act of swimming, stretch of water one can swim across, a strait of the sea," both from Proto-Germanic *sundam-, from *swum-to-, suffixed form of Germanic root *swem- "to move, stir, swim" (see swim (v.)).



early 13c., sounen "to be audible, produce vibrations affecting the ear," from Old French soner (Modern French sonner) and directly from Latin sonare "to sound" (see sonata). From late 14c. as "cause something (an instrument, etc.) to produce sound." Related: Sounded; sounding.

Online Etymology Dictionary, © 2010 Douglas Harper

soundness in Science


  1. A type of longitudinal wave that originates as the vibration of a medium (such as a person's vocal cords or a guitar string) and travels through gases, liquids, and elastic solids as variations of pressure and density. The loudness of a sound perceived by the ear depends on the amplitude of the sound wave and is measured in decibels, while its pitch depends on its frequency, measured in hertz.
  2. The sensation produced in the organs of hearing by waves of this type. See Note at ultrasound.


  1. A long, wide inlet of the ocean, often parallel to the coast. Long Island Sound, between Long Island and the coast of New England, is an example.
  2. A long body of water, wider than a strait, that connects larger bodies of water.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Idioms and Phrases with soundness


In addition to the idioms beginning with sound

  • sound as a bell
  • sound bite
  • sound off
  • sound out

also see:

  • safe and sound
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.