gʰos-ti-
“stranger, guest, host”guest, host, stranger
A PIE nominal root meaning "stranger, one bound by reciprocal hospitality," continued in Latin hostis ("stranger, enemy") and hospes ("host, guest"), whence host, hostile, hospital, hotel, and hospice; and in Germanic *gastiz ("guest"), whence English guest. The root encodes the PIE institution of reciprocal hospitality between strangers.
Discussion
The PIE noun *gʰos-ti- (stranger, guest, host) is one of the most socially and ethically significant words in the reconstructed vocabulary — a single term that meant both "stranger" and "guest," encoding the PIE cultural institution of reciprocal hospitality. The word's semantic duality reflects a world in which the stranger at the door was simultaneously a potential threat and a sacred obligation: every stranger was a future guest, and every guest had been a stranger.
Latin hostis (enemy — originally "stranger") preserves one pole of the semantic range: the stranger as adversary. In archaic Latin, hostis simply meant "foreigner, stranger" without negative connotation; the narrowing to "enemy" occurred during the Republic as Roman identity hardened against outsiders. The derivative hostile (hostile, unfriendly) and the compound hostage (through Old French from Late Latin obsidāticum) continue this adversarial sense.
But Latin also preserves the other pole: hospes (guest, host — from *gʰos-ti-pot-, literally "guest-master," the one who has authority over guests) gave English: host (one who receives guests), hospitable (welcoming to guests), hospital (originally a house for guests and pilgrims — the care of strangers), hospitality, hostel, and hotel (all from the same root via Old French). The word hospital traces from a guesthouse for travelers to a house of care for the sick — one of the most consequential semantic developments in institutional history.
The English word guest itself descends from Old Norse gestr, from PGmc *gastiz, from the same PIE root — making guest and host etymological cousins from the same word. German Gast (guest) confirms the Germanic reflex.
Old Church Slavonic gostĭ (guest) and Russian gostʹ (guest) continue the Slavic reflex. The Russian word for hotel (gostinitsa) preserves the PIE guest-word in modern hospitality infrastructure.
The root's social meaning is profound: the same word for stranger and guest implies a culture in which hospitality was a fundamental obligation — the stranger MUST be received as a guest, and the host MUST provide protection and sustenance. This institution, reconstructed from the vocabulary, matches the customs of hospitality described in Homer, the Vedas, and the Germanic saga literature. The PIE *gʰos-ti- was not merely a word but a social contract encoded in language.
Notes
Pokorny 453. English guest, host, hostile, hospital all from this root.