# thirder

> English word · Noun

## Definitions
1. With regard to the Sleeping Beauty problem: one who argues that the probability of heads is 1/3.

## Etymology
From third + -er.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/thirder