An oar is a long pole with a broad blade at one end, used for rowing a boat. Its default orientation is palewise, blade to chief; its “proper” coloration is brown, the color of wood. The illustration is taken from the arms of the Worshipful Company of Watermen and Lightermen, granted in 1585 [Bromley & Child 256].
Adriana Tacita bears: Per pale purpure and Or, two oars counterchanged.
Finnvarðr mjoksiglandi Grísson bears: Per fess rayonny gules and azure, in chief two oars in saltire argent.
Cato ap Brion bears: Vert, an oar fesswise Or.