What does "zero-grade" mean?

In Proto-Indo-European linguistics, an ablaut form of a root characterized by the absence of the basic ablauting vowel phonemes */e/ and */o/.

What is a synonym for "zero-grade"?

Common synonyms include: vanishing grade.

noun

noun ·Rare ·Advanced level

Noun

1
In Proto-Indo-European linguistics, an ablaut form of a root characterized by the absence of the basic ablauting vowel phonemes */e/ and */o/.
"*bʰr̥- is the zero-grade of the Indo-European root *bʰer- meaning “to carry, bear”."

"*bʰr̥- is the zero-grade of the Indo-European root *bʰer- meaning “to carry, bear”."

From zero + grade, as in gradation (“apophony”). Possibly after German Nullstufe.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.