Our online medical glossary of medical terms and definitions includes definitions for terms related to treatment, and general medicine
GRAINER
1. An infusion of pigeon's dung used by tanners to neutralize the effects of lime and give flexibility to skins; called alsograins and bate.
2. A knife for assume the hairoff skins.
3. One who paints in imitation of the corn of tree, marble, etc.; also, the brush or tool used in graining.
Source: Websters Vocabulary