Where does “山姆” come from?

山姆 (Chinese) comes from English SAM, from Middle English sām, from Old English sāmen, from Proto-Germanic saman, from Proto-Germanic samanai, from Proto-Indo-European sem- — together, one.

Ancestry of “山姆”, step by step

Step	Language	Word	Meaning
1	English	SAM	Initialism of surface-to-air missile; Initialism...
2	Middle English	sām	together
3	Old English	sāmen	together
4	Proto-Germanic	saman	—
5	Proto-Germanic	samanai	at one; together
6	Proto-Indo-European	sem-	together, one

Every word from Proto-Indo-European sem- →Every word from Proto-Germanic samanai →Every word from Proto-Germanic saman →