¹sound

healthy, sound, wholesome, robust, hale, well mean enjoying or indicative of good health. healthy implies full strength and vigor as well as freedom from signs of disease <a healthy family>. sound emphasizes the absence of disease, weakness, or malfunction <a sound heart>. wholesome implies appearance and behavior indicating soundness and balance <a face with a wholesome glow>. robust implies the opposite of all that is delicate or sickly <a lively, robust little boy>. hale applies particularly to robustness in old age <still hale at the age of eighty>. well implies merely freedom from disease or illness <she has never been a well person>.

valid, sound, cogent, convincing, telling mean having such force as to compel serious attention and usually acceptance. valid implies being supported by objective truth or generally accepted authority <a valid reason for being absent> <a valid marriage>. sound implies a basis of flawless reasoning or of solid grounds <a sound proposal for reviving the economy>. cogent may stress either weight of sound argument and evidence or lucidity of presentation <the prosecutor's cogent summation won over the jury>. convincing suggests a power to overcome doubt, opposition, or reluctance to accept <a convincing argument for welfare reform>. telling stresses an immediate and crucial effect striking at the heart of a matter <a telling example of bureaucratic waste>.

The Latin word sonāre, meaning “to make a noise,” gives us the root son. Words from the Latin sonāre have something to do with making noise. A sound is a noise made by someone or something. Something sonic uses the waves noises make as they travel through the air. A sonata is a musical piece in which only one instrument makes noise. To resound is to become filled with noise.