n. the width of a hair, a very short distance or a very small amount
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.
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.
Word Usage
"In short, these kind of hairbreadth missings of happiness look like the insults of Fortune, who may be considered as thus playing tricks with us, and wantonly diverting herself at our expense."