English Reference
numeral · noun

ninth

num. · n.
US /ˈnaɪnθ/ UK /nˈaɪnθ/ ninth UK spelling ninths

  1. 01 A2 Elementary

    num.coming after the eighth and before the tenth.

    num.the ordinal number matching the cardinal number nine in a series.

    Simple

    This is the ninth time I have tried to call the bank today.

    In context

    The ninth chapter of the report provides a detailed breakdown of the fiscal discrepancies discovered during the autumn audit.

  2. 02 B1 Intermediate Math

    n.one of nine equal parts of a whole.

    n.one of nine equal parts into which a whole is or may be divided.

    Simple

    If you cut the cake into nine pieces, each piece is one ninth.

    In context

    The surveyor noted that approximately one ninth of the total acreage was unsuitable for residential development due to the high water table.

  3. 03 C1 Advanced Technical Music

    n.a musical note that is eight notes above another note.

    n.the interval between any tone and the tone represented on the ninth degree of the staff above it.

    Simple

    The composer used a major ninth to create a dreamy, open sound.

    In context

    The pianist struggled with the reach required for the dominant ninth chord in the final movement of the concerto.

It was her ninth goal of the season, the most of any Denver Summit player, and joint-seventh in the NWSL.

The Guardian· 1 Sept 2026

Once the Solar System's Ninth Planet, Pluto Was Reclassified 20 Years Ago.

Smithsonian Magazine· 24 Aug 2026

From Middle English nynthe, nynte, from Old English niġoþa, from Proto-Germanic *newundô; the -n- was reinserted by analogy with nine. Equivalent to nine + -th (ordinal suffix).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin gem-pro *newundô
Level B2 · Upper Intermediate
Frequency Common
Updated