tréyes
“three, the number three”three
PIE word for three. Gives Latin trēs, English "three", Greek treîs, Sanskrit tráyas.
Discussion
The Proto-Indo-European word *tréyes is the cardinal numeral "three" and belongs to the bedrock of Indo-European comparative linguistics. As one of the low numerals, it is among the most securely reconstructed words in the proto-lexicon, with transparent reflexes in every major branch. The number three held deep significance in Indo-European culture, appearing repeatedly in myth, ritual, and social organisation.
In Germanic, the initial *t remained unchanged, and the word descended into Old English þrēo (with the expected Grimm's Law shift of *t to *þ), becoming modern English three. German drei, Dutch drie, and Swedish tre are close cognates. The ordinal third follows the same pattern.
Latin trēs "three" has been spectacularly productive in English: triple, trinity, trident, triangle, tribe (originally a "third" of the Roman people), trivial (from trivium, "a place where three roads meet"), and testament (from testis "witness", originally a "third party"). The prefix tri- appears in hundreds of English technical terms. Greek treis "three" gave English triad, trigonometry, and tripod, while also forming the basis of numerous scientific compounds.
Sanskrit tráyaḥ "three", Old Irish trí, Lithuanian trỹs, Old Church Slavonic trĭje, and Armenian erekʿ (with a more complex development) confirm the numeral across the full breadth of the family.
The cultural significance of three in Indo-European tradition is profound. The tripartite ideology described by Georges Dumézil — the three functions of sovereignty, warfare, and fertility — may reflect a deep structural principle in Proto-Indo-European society. Triple deities, three-headed creatures, and threefold divisions appear throughout Indo-European mythology from India to Ireland. The numeral *tréyes thus carries not just linguistic but cultural weight, encoding one of the foundational patterns of Indo-European thought.
Notes
Source of "triple", "tribe", "trinity", "trident"
Related Roots
English Words from *tréyes
These modern English words descend from this root. Each page traces the full journey from PIE to present-day English.