Nobody knows...
One-syllable words are called monosyllables.
GETTYSBURG
Mouse has only one syllable.
Laugharne's Scoughall's
The words who and owl both have one syllable.
The words "why" and "near" both have one syllable.
The words 'pink' and 'was' have one syllable each.
Monosyllabic (one syllable) words. There is only one syllable so the whole word is stressed.
examples of one syllable words
The words "had" and "bee" both have one syllable each.
All words have at least one syllable. The word "best" has one syllable.
It is a word with one syllable a syllable is a part of the word.