lathekin
/ˈlaðəkɪn/noun
A small, pointed, wooden or plastic tool used by glaziers in making leaded windows, especially to open and straighten the channels in the lead into which the individual panes of glass are set.
Origin
Mid 17th century; earliest use found in James Howell (?1594–1666), historian and political writer. Origin uncertain; perhaps from lath + -kin, although the variety of forms attested is difficult account for.