The Spanish hechizo (“spell”; nothing to do with the letters in words, but what a witch casts on you!) comes from the Latin facticius (“made by art”; “artificial” — indeed, that which is artificial is just something not occurring naturally but instead made by art!).
But how did artificial change to mean “spell”? Think about it this way: casting a spell goes against nature — it’s what the wicked, crazy and profoundly unnatural woman does! Think of the three weird sisters in Macbeth, and how they unnaturally stir up all the elements!
From hechizo (more specifically, from it’s Portuguese twin cognate, feitiço), we get the English fetish. How? Well, you have a fetish when the recipient casts a spell on you to become obsessed with the object of your fetish, right? Enough said!
That root facticius turned into hechizo by changing via two common patterns: the initial F in Latin tended to turn into an H as Latin turned into Spanish (compare fig and higo, or fume and humo!) and the ‑ct- tended to change to a ‑ch- (compare noche and noctural; or ocho and octagon). Thus the h‑ch of hechizo maps to the f‑sh of fetish.
Gremio (Spanish for “union,”, in the sense of workers, unite!; formerly “guild”–which is really just an old-school union!) comes from the Latin Gremium, meaning “round.” How did this transformation happen? Well, a round pen was where you held onto things; it turned into the word for where people got together, which turned into guild (a common reason people got together!) and then, eventually, to mean union.
However, it gets much more interesting. The Latin gremium comes from the proto-indo-european root *ger- meaning.… to get together! From this root, we also get (via Greek) words like congregate (to bring people together) and segregate (to bring people apart!).
Thus, gremio took an interesting turn over the last few thousand years: from the meaning congregate to round to congregate again!
We can see the g‑r root clearly in gremio as well as congregate and segregate.
Yerno (Spanish for “son-in-law”) at first sounds like nothing in English.
But let’s look closer! The g- and y- sounds are often mixed up between languages and even regions that speak the same language; in fact, the Old English g- transformed itself into a y- over time (compare the German gestern with the English yesterday, for example). And the n‑r sound not uncommonly swaps to become an r‑n sound, the two are easily mixed up, especially in slurred speech.
Thus, the bizarre-sounding y‑r-n root of yerno maps to the g‑n-r root of generic (Maybe sons-in-laws are more generic in Spanish cultures than English ones?) as well as genus (which lost the final r-) — yes, genus as in Latin and now scientific classification of your spot in the universe! The son-in-law, I guess, is destined to be the son-in-law as his lot-in-life.
Gota, Spanish for “drop” comes from the Latin gutta for the same. From this root we also get the English gout and… gutter. What is gout, after all, if not a pain that is a constant drip or a gutter, if not a collection of dirty water drops? The g‑l sounds are consistent among all variations.
Esconder (Spanish for “to hide”) comes from the Latin ab- (“away”) and condere (“to put together”). Hiding is, after all, just a form of putting yourself away from everyone else!
From the same root we get the less common English abscond, “to secretly run away to avoid capture.” That is just hiding–but taken to the extreme!