from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Extremely close: a hairbreadth escape.
- n. Variant of hairsbreadth.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. the width of a hair, a very short distance or a very small amount
from the GNU version of the Collaborative International Dictionary of English
- The diameter or breadth of a hair; a very small distance; sometimes, definitely, the forty-eighth part of an inch.
- adj. Having the breadth of a hair; very narrow.
from The Century Dictionary and Cyclopedia
- n. The diameter or breadth of a hair; an infinitesimal space or distance. Among the Jews a hairbreadth was reckoned the 48th part of an inch; in Burma it is of an inch. Now generally written hair's-breadth.
- Of the breadth of a hair; extremely narrow.
From hair + breadth. (Wiktionary)