speḱ-
“to look, to observe”look, see, observe
Root for looking/observing, yielding Latin specere, English spy, scope, spectacle.
Discussion
The PIE noun *gʷṓws (cow, bull, bovine) is the word for the most economically important domesticated animal in the PIE world — the source of milk, meat, leather, and traction power that formed the foundation of the pastoral economy reconstructed from comparative vocabulary. The word's survival across every branch confirms its PIE antiquity and the centrality of cattle to the proto-culture.
Latin bōs (ox, cow — genitive bovis) shows the expected Italic treatment of the labiovelar *gʷ > Latin b. The derivatives include: bovine (pertaining to cattle), beef (from Old French boef, from Latin bovem — making beef a French-dressed Latin cow-word), butter (from Greek boútȳron, "cow-cheese," literally bou- + tȳrós), and bucolic (from Greek boukolós, "cowherd" — pastoral poetry named after the cattle-tender).
Greek boûs (βοῦς, "ox, cow") continues the form with the expected Greek treatment. The word appears in compounds of unusual cultural weight: hecatomb (hekatón + boûs, "a hundred cattle" — the greatest sacrificial offering), boustrophedon ("as the ox turns" — an ancient writing system that alternates left-to-right and right-to-left, mimicking an ox ploughing a field), and the personal name Bucephalus (bou- + kephalḗ, "ox-head" — Alexander the Great's horse).
English cow descends from Old English cū, from PGmc *kūz, from PIE *gʷṓws with the regular Grimm's Law shift: PIE *gʷ > PGmc *k. German Kuh, Dutch koe, and Old Norse kýr continue the same form. The word has been in continuous use since before the PIE dispersal — cow is one of the oldest words in English, older than English itself by several thousand years.
Sanskrit gáu- (cow, bull) and the related go- continue the root in Indo-Iranian. The word is sacred in Hindu tradition: the cow's inviolability in Indian culture is reflected in the vocabulary (gopāla, "cow-protector," a name of Krishna). The Avestan gāuš confirms the Iranian reflex.
Old Irish bó (cow) provides the Celtic attestation — visible in the ancient Irish tale Táin Bó Cúailnge ("The Cattle Raid of Cooley"), the central epic of the Ulster Cycle, whose plot revolves around the theft of a prize bull. The role of cattle in Irish mythology mirrors the PIE pattern: cattle are wealth, and cattle-raiding is the activity that drives narrative.
The word's universal preservation — in every major branch, with the same meaning — makes *gʷṓws one of the most diagnostic items in PIE pastoral vocabulary and one of the strongest arguments for the cattle-herding economy of the proto-culture.
Notes
Pokorny 984-985. English inspect, respect, suspect, spectrum.