THE FULL ARTICLE — from the International Standard Bible Encyclopedia

The International Standard Bible Encyclopedia (1915), general editor James Orr — public domain, printed whole.

o'-ker, (Isa 44:13, "He marketh it out with a pencil," margin "red ochre," the King James Version "line"; seredh, a word found only here, and of unknown etymology): Designates the implement used by the carpenter to mark the wood after measuring and before cutting. "Red ochre" supposes this to have been a crayon (as does "pencil"), but a scratch-awl is quite as likely. Ochre is clay colored by an iron compound.