1) The hard material of an animal's horn, used in a variety of manufacturing.
From the Middle Ages, horn was commonly employed to make a variety of artefacts: 1656 Item three dozen of horn spoones 2s 3d, Eshton. It was used also to make knife handles, and the inventories of Sheffield's cutlers frequently refer to stag horns, buck horns and rams horns. In 1719, a Sheffield innkeeper called Zachariah Arthur had Nine Buck horn Knives and Forks worth Ł1 1s 0d
in 1724 John Downes, a Sheffield factor, had 24 Head rams Horns for sale and in 1730 Robert Rhodes, a cutler, had 113 head of buck horns at 8d per head . The cutlers’ familiarity with the material helps to explain the success of button-making in Sheffield from the seventeenth century.
2) As a verb, to furnish with horn.
1421 Thomć Hornar de Petergate pro horning et naillyng superscriptorum librorum, York. Hornpot Lane in York is where horn was processed and it gave rise to an unusual by-name: 1247-62 Richard Hornpotte, Petergate
1281-2 Nicholas Hornepot, Petergate.