古英語のhelma、オール、舵、原語ゲルマン語の*halbma、PIE *kelp、つかむ、保持、語源的にはhalter、helve、助けるから。
Helm - the handle or tiller, in large ships the wheel, by which the runner is managed; the word is sometimes used with reference to the whole stearing-gear.
Rudder - that part of the helm which consists of a broad piece of timber, enters the water, and is governed by means of the wheel or tiller.
Tiller - the bar or lever by means of which the rudder of a ship or boat is turned.
[J.H.A. Günther, "English Synonyms Explained & Illustrated," Groningen, 1904]