terpin

from The Century Dictionary.

• noun Either of two compounds, designated respectively as cis- and trans-. They are space isomers, the latter being the more important. It is prepared from transcineol-hydrobromide, and crystallizes in highly lustrous short prisms or plates melting at 156–158° C. and boiling at 263–265° C. Also called terpin hydrate.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Chem.) A white crystalline substance regarded as a hydrate of oil of turpentine.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun obsolete, medicine Any of several preparations, primarily of terpineol, used medicinally