*Ghos-ti- derivation

From The American Heritage College Dictionary, the Proto-Indo-European appendix:

ghos-ti- Stranger, guest, host; properly “someone with whom one has reciprocal duties of hospitality.” 1. Basic for *ghos-ti-. a. (i) GUEST, from Old Norse gestr, guest; (ii) GASTARBEITER, from Old High German gast, guest. Both (i) and (ii) from Germanic *gastiz; b. HOST², HOSTILE, from Latin hostis, enemy (< “stranger”). 2. Compound *ghos-pot-, *ghos-po(d)- “guest-master,” one who symbolizes the relationship of reciprocal obligation (*pot-, master; see poti-). HOSPICE, HOSPITABLE, HOSPITAL, HOSPITALITY, HOST¹, HOSTAGE, HOSTEL, HOSTLER, from Latin hospes (stem hospit-), host, guest, stranger. 3. Suffixed zero-grade form *ghs-en-wo-. XENIA, EXNO-, XENON; AXENIC, PROXENE, from Greek xenos, guest, host, stranger. [Pokorny ghosti-s 453.]