mode (n.1)
"manner," late 14c., "kind of musical scale," from Latin modus "measure, extent, quantity; proper measure, rhythm, song; a way, manner, fashion, style" (in Late Latin also "mood" in grammar and logic), from PIE root *med- "to measure, limit, consider, advise, take appropriate measures" (see medical). Meaning "manner in which a thing is done" first recorded 1660s.
mode (n.2)
"current fashion," 1640s, from French mode "manner, fashion, style" (15c.), from Latin modus "manner" (see mode (n.1)).