All of these definitions denote some sort of closeness, usually benign. Such are listed on most etymology sites. But as usual, a more obscure context hides in the shadows, waiting to flip one's perception of everything.

In chess, a checkmate occurs when a king is placed into a position where he cannot escape; this is given in Persian as shāh māt — the king is at a loss. However, when the Arabs borrowed this phrase, it became al-shāh māta — the king has died.¹ The verb māta is the version that made its journey towards Europe and beyond.

It is rather funny that mate and checkmate look to have been popularized around the same time, starting around the 14th century. Other words come to mind: 

- matar ("to kill" in Spanish and Portuguese)

-- matador ("killer" in Spanish; in bullfighting, they kill bulls)

- mort (French for "death" or "to have died" [present perfect]--, such as in the phrase "Le roi est mort, vive le roi!" - The king has died, long live the king, which originated from 1422

It looks as if the term mate carries darker implications than what are usually known to us. For one, since a shipmate is below a captain in rank, one could interpret this as them being able to be disposed of by their superiors. Additionally, it's ironic that mating is considered as bringing life to new friends², love, and babies, when the aforementioned contexts show it to mean cutting down those parts of life.

Thanks for reading! Me is open to discussion of this matter! More to come!

¹Moghadam, M. E. (1938). A Note on the Etymology of the Word Checkmate. Journal of the American Oriental Society, 58(4), 662–664. JSTOR. https://doi.org/10.2307/594376

²The presence of friendliness or cordiality does not denote friendship; amity looks like the most fitting term (like with amend or ameliorate)