"coniferous tree," Old English pin (in compounds), from Old French pin and directly from Latin pinus "pine, pine-tree, fir-tree," perhaps in reference to the sap or pitch, from PIE *peie- "to be fat, swell" (see fat (adj.)). Cf. Sanskrit pituh "juice, sap, resin," pitudaruh "pine tree," Greek pitys "pine tree." Also cf. pitch (n.1). Pine-top "cheap illicit whiskey," first recorded 1858, Southern U.S. slang. Pine-needle (n.) attested from 1866.
Old English pinian "to torture, torment, afflict, cause to suffer," from *pine "pain, torture, punishment," possibly ultimately from Latin poena "punishment, penalty," from Greek poine (see penal). A Latin word borrowed into Germanic (cf. Middle Dutch pinen, Old High German pinon, German Pein, Old Norse pina) with Christianity. Intransitive sense of "to languish, waste away," the main modern meaning, is first recorded early 14c. Related: Pined; pining.