starboardyoudaoicibaDictYouDict[starboard 词源字典]
starboard: [OE] Starboard is etymologically ‘steer-board’. The word originated as an Old English compound formed from stēor ‘paddle, rudder’ (a relative of the verb steer) and bord ‘board’. The early Germanic peoples propelled and steered their boats by means of a paddle on the right-hand side of the vessel – hence the use of starboard as the nautical equivalent of right.
=> steer[starboard etymology, starboard origin, 英语词源]
starboard (n.)youdaoicibaDictYouDict
Old English steorbord, literally "steer-board, side on which a vessel was steered," from steor "rudder, steering paddle," from Proto-Germanic *steuro "a steering" (compare German Steuer), from PIE *steu-, secondary form of root *sta- "to stand" (see stet) + bord "ship's side" (see board (n.2)). Similar formation in Old Norse stjornborði, Low German stürbord, Dutch stuurboord, German Steuerbord.

Early Germanic peoples' boats were propelled and steered by a paddle on the right side. The opposite side of the ship sometimes in Germanic was the "back-board" (Old English bæcbord). French tribord (Old French estribord), Italian stribordo "starboard" are Germanic loan-words.