The English recruit and the Spanish crecer (“to grow”) seem like they have nothing to do with each other. But looks can be deceiving!
“Recruit” comes from, via French, the roots re- (“again”) and theh Latin crescere, meaning “to grow” — from which we get the Spanish for the same.
Therefore, a recruit is literally a “new growth” — it is how the next generation is reborn!
Interestingly, we also get from the same root the English crescent as well.