dʰwer-
“door, gate”door, gate, entrance
Root for door/gate, yielding Latin foris/fores, English door, Greek thyra.
Discussion
The Proto-Indo-European root *dʰwer- denoted "door, gate, doorway" and represents one of the oldest architectural terms recoverable from comparative reconstruction. Latin produced foris "door" (plural forēs "double doors"), whence forānus "outside" and eventually English foreign — that which lies beyond the door. The Latin forum likewise derives from this root, originally denoting the outdoor space before the door. Greek θύρα (thyra) "door" is traced to the root with the expected aspiration pattern, a form preserved in English thyroid (the shield-shaped cartilage, named from thyreos, a door-shaped shield). The Germanic reflex appears with full regularity: English door (Old English duru, dor) and German Tür continue the root with Grimm's Law applied. Sanskrit dvār- (dvāram, "door, gate") confirms the Indo-Iranian branch. That the same word gave rise to both door and foreign tells us that for Proto-Indo-European speakers, the doorway was the fundamental boundary between the known interior and the alien world beyond.
Notes
Pokorny 278-279. English door, foreign, forum, forest.
Related Roots
English Words from *dʰwer-
These modern English words descend from this root. Each page traces the full journey from PIE to present-day English.