The Spanish for “cow” vaca, comes from the Latin vacca, meaning the same. From that same root, we get the English…. vaccine/em.
Huh? How?
Interestingly, the first, umm, vaccine, was to give the cow-pox virus to people with small-pox! Thus, the word for cow turned into the word for vaccine!
We can see the v-c root clearly in both.