• 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 )
• 3. of or relating to radio as distinguished from television
• 4. the sensation produced by such a periodic disturbance in the organs of hearing
• 5. anything that can be heard
• 6. a particular instance, quality, or type of...

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• 1. free from damage, injury, decay, etc
• 2. firm; solid; substantial
• 3. financially safe or stable
• 4. showing good judgment or reasoning; sensible; wise
• 5. valid, logical, or justifiable
• 6. holding approved beliefs; ethically correct; upright; honest
• 7. (of sleep) deep; peaceful; unbroken
• 8. thorough; complete
• 9. excellent
• 10. (of a title, etc) free from defect; legally valid
• 11. constituting a valid and justifiable application of correct principles; orthodox
• 12. (of a deductive argument) valid
• 13. (of...

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• 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. (of a whale, etc) to dive downwards swiftly and deeply
• 4. to probe or explore (a bodily cavity or passage) by means of a sound
• 5. to examine (a patient) by means of percussion and auscultation
• 6. an instrument for insertion into a bodily cavity or passage to dilate strictures, dislodge foreign material, etc
• 7. See also sound out
• 8. C14: from...

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

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