Entry Word: hairline

Function: adjective

Meaning: 1 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> — see narrow 1
2 made or done with extreme care and accuracy <a hairline distinction between her rating of certain things as “necessary” and others as “absolutely necessary”> — see fine 2
3 meeting the highest standard of accuracy <an ultra-sensitive telescope that requires hairline placement of the lenses> — see precise 1