From the Latin fundus (“bottom”), we get the Spanish fondo (“background”) and hondo (“deep”) — as well as the English profound. After all, when someone says something profound, well, that’s deep.
The mapping of the Spanish f-n-d (or h-n-d) to the English (pro)-f-n-d is straightforward. However, it’s curious that, in hondo, the initial F transformed from Latin into Spanish to an initial H. This is a common pattern, unique to Spanish, that we see in many Latin words as they transformed into Spanish, such as hijo and filial, refuse and rehusar, and higado and fig.
The Spanish “Huir” comes from the same Latin root as “fugitive”, “fugitivus”, meaning, “to flee”.
Pattern: Latin words that began with an ‘F’ tended to lose that initial ‘F’ sound and became silent (yet represented in writing with an ‘H’) as vulgar Latin turned into Spanish.
Hierro is just Spanish for “iron”.
Here’s where it gets interesting: the Latin words beginning with f- generally turned into the silent h- in Spanish but not in the other Romantic languages, and thus hierro (from the Latin ferrum) is related to:
The Spanish for “son”, hijo, doesn’t sound like anything in English. But it is a close cousin of the English synonym for brotherliness: filial.
Both come from the Latin for “son,” filius. The transformation to Spanish came about through two interesting patterns: the initial f- in Latin usually turned into an h- in Spanish (such as, hacer and fact, or hablar and fable). The other pattern is less common: the -li- sound turned into a -j- sound – it’s just a less common sound! Thus the f-li maps to h-j almost exactly.
From the Latin filius, we get a few other English words, including: affiliate: an affiliate is, in a way, a child you rear!
From the same root we also get the English fetus, fecund and even feminine. These come, via the Latin filius, from the Proto-Indo-European root *dʰeh₁y-li-os, meaning, “sucker” — in the literal sense of, “one who sucks.” Children, indeed, are defined by their sucking their mothers; so your hijo is literally, “the one who sucks.” And, some might argue, even affiliates themselves usually do suck!
The Spanish hongo, for “mushroom,” doesn’t sound anything like its English counterpart “mushroom.” But it does come from the Latin fungus from which we get the English synonym for mushroom… fungus.
The relation between hongo and fungus is easy to remember if we remember that, as Latin evolved into Spanish, the initial f- (followed by a vowel) usually transformed into an h-. Thus, the f-n-g for fungus maps exactly to the h-n-g of hongo.