A pine is any conifer in the genus Pinus, , of the family Pinaceae. "Pinus" is the sole genus in the subfamily Pinoideae. The Plant List compiled by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts 126 species names of pines as current, together with 35 unresolved species and many more synonyms. 

The modern English name "pine" derives from Latin "pinus", which some have traced to the Indo-European base *pīt- ‘resin’ (source of English pituitary). Before the 19th century, pines were often referred to as firs (from Old Norse "fura", by way of Middle English "firre"). In some European languages, Germanic cognates of the Old Norse name are still in use for pines—in Danish "fyr", in Norwegian "fura/fure/furu", Swedish "fura/furu", Dutch "vuren", and German "Föhre"—but in modern English, "fir" is now restricted to fir ("Abies") and Douglas fir ("Pseudotsuga"). 

Pines are gymnosperms. The genus is divided into three subgenera, which can be distinguished by cone, seed, and leaf characters: 

Most regions of the Northern Hemisphere (see List of pines by region) host some native species of pines. One species (Sumatran pine) crosses the equator in Sumatra to 2°S. In North America, various species occur in regions at latitudes from as far north as 66°N to as far south as 12°N.
when?
Before the 19th century