Etymology From Middle English helmet, helmett, a borrowing from Old French helmet, heaumet, a diminutive of helme (Modern French heaume), equivalent to helm + -et. The Old French is itself of Germanic origin (whence Old English helm). Used in English since the 15th century, it has largely displaced helm as the general word.
Now that she had rested and had fed from the luncheon tray Mrs. Broome had just removed, she had reverted to her normal gaiety. She looked cool in a grey tailored cotton dress with a terracotta scarf and shoes and her hair a black silk helmet.1963, Margery Allingham, chapter II, in The China Governess: A Mystery, London: Chatto & Windus, →OCLC:
Most speedboarders wear helmets, knee and elbow pads, and occasionally all-in-one aerodynamic suits, to protect themselves.2009 February 25, Noam Friedlander, “Dangerous sport of speedboarding banned from Malibu streets”, in The Daily Telegraph:
Etymology From Middle English helmet, helmett, a borrowing from Old French helmet, heaumet, a diminutive of helme (Modern French heaume), equivalent to helm + -et. The Old French is itself of Germanic origin (whence Old English helm). Used in English since the 15th century, it has largely displaced helm as the general word.
1
To cover with, or as if with, a helmet.
There was no nonsense about these women—no hysteria, no top-note emotion. They were not out for smashing windows or helmetting policemen, or blowing up things sky-high.1913 August 28, “English Non-Militant Suffragists in Parade”, in The Union Signal, volume XXXIX, number 35, Evanston, Ill., page 12:
COMRADE, I had done well with you to swear / Allegiance to the colors of romance / In the great days when our sweet mistress, France, / Girded her loins and helmetted her hair.1917 August, Walter Adolphe Roberts, “To a Friend Fallen for France (Alan Seeger)”, in The Forum, volume LVIII, New York, N.Y.: The Forum Publishing Company […], page 210:
1 more example
And then they’re fleeing in a second rain of meteorites, their arms helmetting their heads, as they run away from us.2014, Jandy Nelson, I’ll Give You the Sun, New York, N.Y.: Dial Books, →ISBN, page 96: