eighth

• eight (obsolete)
• eightth (nonstandard)

Inherited from Middle English eiȝtthe, from Old English eahtoþa, from Proto-Germanic *ahtudô; equivalent to eight +‎ -th (ordinal suffix).

• (Received Pronunciation) enPR: ātth, IPA^(key): /eɪtθ/
• (General American) enPR: ātth, āth, IPA^(key): /eɪtθ/, /eɪθ/

  • Audio (US):

    (file)

• (Indic) IPA^(key): /ɛj(ʈ)t̪ʰ/, (pane–pain merger) /e(ʈ)t̪ʰ/
• Rhymes: -eɪtθ, -eɪθ

eighth (not comparable)

1. The ordinal form of the number eight.
   • 2022, “2023 Laws of Chess”, in FIDE‎^[1], page 21:

     Consequently, in the initial position the white pieces and pawns are placed on the first and second ranks; the black pieces and pawns on the eighth and seventh ranks.

   • 2025 February 25, “South Korea’s birth rate rose for the first time in 9 years. Is the world’s lowest fertility rate on the rebound?”, in CNN‎^[2], sourced from Reuters, archived from the original on 6 July 2025:

     In 2023, the birthrate fell for the eighth consecutive year to 0.72, the lowest in the world, from 1.24 in 2015, raising concerns over the economic shock to society from such a rapid pace.

• 8th, 8^th, VIIIth; (in names of monarchs and popes) VIII

eighth (plural eighths)

1. The person or thing in the eighth position.
2. One of eight equal parts of a whole.

   Two bits equals two eighths of a dollar.

   • 2000 October 3, Eric Nagourney, “VITAL SIGNS: PROTECTION; A Measure of an Infant Skull's Strength”, in The New York Times‎^[3], archived from the original on 19 April 2022:

     Scientists from the University of Pennsylvania have determined that the young skull is only an eighth as strong as an adult one.

3. (slang) An eighth of an ounce, or approximately 3.5 grams, of marijuana or other drugs.
   • 2000, Zadie Smith, White Teeth, London: Penguin Books, published 2001, →ISBN, page 499:

     At midday he’d found an ageing eighth of hash in a drawer, a little bundle of cellophane.

4. An interval by doubling in pitch frequency.

• (person or thing in the eighth position): eighth one
• (One of eight equal parts): ⅛, half-quarter, henry (for an eighth of an ounce of marijuana in the UK)
• (⅛ oz.): ochava (historical Spanish contexts)
• (twice the frequency): octave

• (One of eight equal parts): epogdoon (a number greater by a ratio of nine to eight; 1+¹⁄₈)

eighth (third-person singular simple present eighths, present participle eighthing, simple past and past participle eighthed)

1. (transitive) To divide by eight.
   • 2013, Raindance Producers' Lab Lo-To-No Budget Filmmaking‎^[4], page 31:

     The first step is to eighth the script out. See figure 3.6 overleaf. Eighthing a script is subjective.

• octave

• Height, Highet, height, highte