terh₂-
“to cross over, to pass through”through/cross
PIE root meaning to cross over or pass through. Source of Latin trāns, English "through," and words for transit and crossing.
Discussion
*terh₂- is a Proto-Indo-European root meaning "to cross over" or "to pass through," yielding vocabulary for transit, crossing, and boundary traversal.
Latin trāns "across" (whence English trans-, transport, translate, transcend, transform, transit, transparent, and many more) is the primary derivative. The prefix trans- remains fully productive in English. Latin intrāre "to enter" (literally "to go within") and English enter derive from a compound with *h₁en + *terh₂-.
Sanskrit tárati "crosses, overcomes" and tīrṇá- "crossed" preserve the verbal root. The concept of "crossing over" extends to overcoming obstacles, visible in Sanskrit avatar (avatāra-, "descent," literally "crossing down"). Greek terma "boundary, end point" (whence English term, terminal, terminate, determine) reflects the place where crossing occurs.
In Germanic, Old English þurh "through" (modern English through, thorough) derives from this root with Grimm's Law (*t > þ). German durch "through" continues the pattern.
Modern descendants include English through, thorough, trans- (transport, translate, transcend), term, terminal, and nostril (from nose-thirl, "nose-hole/passage").
Notes
Source of Latin "trāns" (across), English "through". Traversal root.