1
as in thin
being of less than usual width
a hairline crack in the mug, almost too small to notice, was enough to make the mug break when filled with hot tea
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2
as in subtle
made or done with extreme care and accuracy
a hairline distinction between her rating of certain things as "necessary" and others as "absolutely necessary"
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3
as in mathematical
meeting the highest standard of accuracy
an ultrasensitive telescope that requires hairline placement of the lenses
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as in inch
a very small distance or degree
the controversial measure passed by a hairline, the margin of victory being but a single vote
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Cite this Entry
“Hairline.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/hairline. Accessed 10 Jul. 2026.
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