Duo
来自Big Physics
late 16th century (in duo (sense 2)): via Italian from Latin duo ‘two’.
wiktionary
From French duo or Italian duo, from Latin duo(“two”), from Proto-Indo-European *dwóh₁. Doublet of two, from Proto-Indo-European.
etymonline
duo (n.)
1580s, "song for two voices, duet," via either Italian or French from Latin duo "two" (from PIE root *dwo- "two"). Meaning "two people" (especially as an entertainment team) attested by 1887.
