ox gall

noun

variants or less commonly oxgall or ox-gall

ˈäks-ˌgȯl 

1

: bile obtained from an ox

2

: a preparation consisting of alcohol mixed with ox bile that is used chiefly as a wetting agent (as for watercolors)

… painting large, flat areas in gouache can be difficult because of its tendency to streak. Adding a few dozen drops of ox gall to the cup of mixing water can minimize streaking by slowing drying time …

—Linda S. Price

Word History

First Known Use

15th century, in the meaning defined at sense 1

Medical Definition

ox gall

noun

variants also oxgall or ox-gall

-ˌgȯl 

: bile obtained from an ox : bile salts sense 2