Deep & hollow
The word deep comes from an old word meaning deep & hollow. Though the people who used this ancient root never wrote it down, etymologists write it *dheub-. Like our modern word, deep, the original root also carried the figurative meanings profound, inspiring, solemn, mysterious, awful.
Of course, *dheub- was far too deep a word to give us only the word deep.
About the year 1200, it gave us dive, to descend or plunge headfirst into water. Because we’re approaching International Dive Bar Day (July 7), I’m compelled to note that the idiom dive bar was born in the 1800s. It appears to have come from the fact that many low-end drinking establishments could only be accessed by walking downstairs from street level, thus diving into the bar.
Quarrelsome as they are, etymologists are still duking it out over the etymology of typhus & typhoon. They may have come from Arabic, Mandarin, Cantonese, or Greek. They may have come from *dheu-, a form of *dheub that meant smoke. Or they may have come directly from *dheub-. I suppose both typhoon & typhus can be seen to embrace the concept of depth.
Python also inspires fistfights among the more pugnacious etymologists. One camp hangs its hat on the story of Apollo slaying the serpent near Delphi, which was originally called Pythein, a word meaning to rot. The alternative camp finds our ancient root *dheub- responsible for python, as monsters such as serpents were often believed to inhabit the depths.
Interestingly, the surname Donald also comes from this root. Donald showed up in English in the 1200s from Scottish (though the name in Scottish was either Dofnald or Dufenald). It entered Scottish from Proto-Celtic, where it was something more like Dubno-valos, & meant ruler of the world, valos meaning to be strong & dubno (from the root *dheub-) meaning world. And how did a word meaning deep & hollow end up meaning world? All that depth oozed into meaning bottom or foundation, & the earth or world appeared to be the foundation of things.
So this one root has something to do with hollow, deep, storm, plunging headfirst, disease, foundation, world, even monster habitat. Yikes. Some etymologies offer those combative etymologists more grist than others, eh?
Big thanks to this week’s sources: Merriam Webster, Phrases.org, Lexico, Collins Dictionary, Wordnik, & Etymonline.