The two crossword solutions for the term 'resin used in varnishes' are MASTIC (6 letters) and ELEMI (5 letters). MASTIC is a resin obtained from the MASTIC tree, which is native to the Mediterranean region. It has been used since ancient times as a sealant and adhesive, and is still used today in varnishes, lacquers, and other coatings. ELEMI is a resin obtained from the ELEMI tree, which is native to the Philippines. It has been used since ancient times as an incense and medicine, and is still used today in varnishes, lacquers, and other coatings.