Although encontrar, the common Spanish word for “to meet”, doesn’t sound like its English counterpart, it does have an unexpected first cousin: acquaint.
Both come from the same Latin root for the same (in contra), although the English one comes to us via the French influence: acointier.
Thus, we can see that the en-c-n-t‑r maps to a‑cqu-n‑t somewhat closely: the final -r disappeared as the French word evolved into the English word, and the opening en- (in- in Latin) became the simpler a-.
Someone you meet, after all, is indeed your acquaintance.
There is, however, another English word that is closer to encontrar although perhaps less obvious until you hear it: encounter!