The Spanish hembra, for “female” (usually in regard to animals) sounds nothing like the English feminine. But it turns out that they are etymologically identical.
Both come from the Latin for female, feminina. Hembra sounds so different because the f-m-n root is changed to h-mbr via two different patterns:
- The f-to-h pattern, where words beginning in the Latin f- change to an h- in Spanish, such as filial and hijo, or hacer and fact — changing the initial h- of feminina to h-.
- The m-n to -mbr- pattern, where Latin words with the m-n together usually changed to an -mbr- in Spanish, like illuminate and alumbrar — changing the m-n of feminina to the -mbr- of hembra.
These two, taken together, show a clear mapping of f-m-n to h-mbr.