The word tenacious has survived in the English language for over four centuries (you could almost say that it was tenacious). Although it now has a more figurative meaning of "difficult to sway from one's beliefs", as the Middle French word tenacite, it meant something more literal, along the lines of "clinging on" (although that is also a remaining definition today, of course; there is a shift, however). In Latin as tenacitas, the translation is "the act of holding fast", and that traces to the verb tenere, meaning "to hold" (Spanish speakers can recognize this as the etymon of tener, "to have". Earlier, in Proto-Italic, etymologists reconstruct this to a word sounding like teneo, and that in turn would be from Proto-Indo-European ten, meaning "to stretch". Ten is interesting because of the sheer number of words that spawned from it; among those that include it as a root are abstain, baritone, catatonic, detain, entertain, hypotenuse, intend, maintain, ostensible, pertain, sustain, temple, and tenure. The list goes on and on. Like derivation, like etymon: it certainly is tenacious.
Adam Aleksic, a leading contender for valedictorian of his high school, is a 215-month-old boy with disturbing interests in etymology, vexillology, geography, and law. Adam would like to one day visit Tajikistan and probably isn't spying for the Uzbek government.
The Etymology Nerd