I was somewhat taken aback when I peeked in the Oxford English Dictionary looking for the word sound .
The word merits 13 main entries and approximately 15,000 words of text—that's about 50 pages of text. Most of the meanings of sound you'll already know: for example “an arm of the sea” as in Nantucket Sound; “strong and healthy,” as in of sound mind ; or “sounding the depths” to see how deep the water might be; and of course sound as we experience it in our ears. We are all aware that new words are coming into English all the time, but we usually forget when an old word or meaning falls out of English.
That's actually why if falls out of English, because we forget about it. One meaning that fell out of English is one of the OED entries for sound; it once also meant “the action or power of swimming.” The sound we hear in our ears came to English in 1297 and for several centuries it was pronounced as had been the French word it grew out of. In French sounee means “to call” and until the time of Shakespeare sound was pronounced “soun” in English; without the “d.” The roots of this word go back before French to the Latin sonum or sonus which also is at the heart of sonar, the name of the technology that bats use to “see” with sound. This Latin root is even in the name of the musical instrument bassoon which literally means “deep sound.” The sense of “strong and healthy” does not come from a Latin root but instead from a Germanic one. In Old English it was something like gesund .
The phrase “sound as a bell” appears as far back as 1565 and may have survived because it represents a pun. Something “sound as a bell” is “strong and healthy” but a bell produces sound you can hear.
Other similar phrases have gone the way of the dodo.
How would you react to being called “sound as a roach”?
Don't take offense. For this phrase from the 1650s a roach is not a bug, but instead a kind of fish.
Being said to be as sound as a roach was actually a compliment as proven by the similarly obsolete phrase “sound as a trout.” Around that same time, in the mid 1600s, if someone said you were “sound as a trout” it meant that you were a good solid friend.
