Batir (Spanish meaning, “to beat”) and its very common derivative, batido (meaning “milkshake” — you beat the ingredients together after all!) both come from the Latin battuere meaning the same, “to beat.”
From that same Latin root we get the English battery — think of the phrase, assault and battery! (Over time, the meaning shifted from beating, to artillery — that which beats the enemy to the ground, literally! — and then from there, to the electric power that powers the artillery, and from there, our more common modern definition of the word.) And batter, like the mixture you make while cooking — that’s you beating the eggs together, right?
The b-t root is visible in all these words.
Remo comes from the Latin for the same, remus, while the English came from the German ruejen; both of those come from Proto-Indo-European *ere, meaning “to row”.
We can see the r- maps to the r- in each and it does make sense. After all, you do use an oar to row.
The English chain is disfigured from the original for a few reasons. Since the English came to our language via the French, the initial c- changed into a ch-, as so often French does. French additionally has a tendency to drop letters: the middle -d- in this case. Thus, the c-(d)-n of cadena maps to the ch-n of chain!
From the same root, we have a more obvious connection–but a more obscure word. Concatenate, a nerdy word meaning “to add together” that really only software developers remember these days, comes from the same root. We can thus see the c-d-n of cadena very easily in the c-t-n of concatenate, remembering the very common -d- and -t- swapping. Concatenate begins with the con- prefix (“together” in Latin, like the Spanish “con”) — and what is a concatenation, if not just adding together a bunch of nodes in a chain?
From this root, we also get the English name… Timothy. The -thy ending comes from the Greek theo-, meaning, “God” — so Timothy is literally, one who is scared of God.
From the same root, we also get the less common… temerity, which just means “boldness”: and what is being bold if not, not having any fear?
This, indeed, makes sense: what is a wedding if not just a vote in the other person, and a promise to be with them? At least in Spanish it is. (The other word for wedding in Spanish, casamiento, is related to the Spanish for “home”, casa).
This one isn’t obvious, at all, based on the spelling, but it is based on the sound. One lesson is to guess parallel words based on the sounds more than the letters. But pay attention to the letters when they are unexpected or voiced weirdly.