Etymograph

English

tera-

Tera- comes from Ancient Greek τέρας ‘monster’.

  1. Ancient Greekc. 800–300 BCEτέρας1téras‘monster’
  2. Englishtodaytera-1

attested reconstructed ? uncertain or disputed deepest recorded ancestor

  1. 1 Wiktionary, English tera-

Earlier history uncertain. See Wiktionary.

Lineage

  1. Ancient Greekc. 800–300 BCEτέραςWiktionary, English tera-téras‘monster’
  2. Englishtodaytera-Wiktionary, English tera-

The story

Also from Ancient Greek τέτταρες (téttares, “four”), by analogy with tetra- for being the fourth power of 10³.

Full etymology on Wiktionary

Every English word from Ancient Greek τέρας

Today it means

prefix In the International System of Units and other metric systems of units, multiplying the unit to which it is attached by 10¹² (short scale trillion or long scale billion).

Sources

Sources: Wiktionary, “tera-”. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.

Etymograph / Ancient Greek τέρας / tera-

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