1) Medium 2) Megalp 3) Oil color vehicle 4) Painting material 1) Megalp 
Megilp p also known as Macgilp and McGuilpis is an oil painting medium consisting of a mixture of mastic varnish and an oil medium: such as walnut, linseed, safflower, poppy, black oil (linseed oil) cooked with litharge or white lead etc. Earlier recipes may omit the mastic and substitute wax It makes oil paint thin, glossy, and easy to work, with...
• (n.) Alt. of Megilph
(from the article `mastic`) ...from incisions in mastic trees. It is used chiefly to make pale varnishes for protecting metals and paintings. When dispersed in bodied (thickened ...
(also termed
Megilp is a substance added to graining colour to prevent it from flowing together and to help it to retain its sharpness of definition after it has been combed or figured. Skilled grainers often prepare their own meglip to secret recipes.
[n] - a medium for oil-paints
megalp noun a medium for oil-paints; linseed oil mixed with mastic varnish or turpentine