Rosin
Properly "naphtha," as it is both in the LXX. and the Vulgate, as well as in the Peshito-Syriac. Pliny mentions naphtha as a product of Babylonia, similar in appearance to liquid bitumen, and having a remarkable affinity to fire.
Bibliography Information Smith, William, Dr "Definition for 'Rosin' Smiths Bible Dictionary". bible-history.com - Smiths; 1901.