# T4 vs TD

> English confusable word pair

## The two words

### T4
*noun · IPA /ˌtiːˈfɔː/ · frequency rank #29,116*
Abbreviation of tetraiodothyronine (“thyroxine”).

### TD
*noun · frequency rank #8,492*
Abbreviation of touchdown.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-09-03.
Canonical page: https://plainspell.com/en/vs/t4-vs-td