Pronunciation: (hâr'līn"),[key] —n. 1. a very slender line.
2. the lower edge of the hair, esp. along the upper forehead: a hairline that slowly receded. 3. worsted fabric woven with very fine lines or stripes.
4. Print. a. a very thin line on the face of a type. See illus. under type. b. a style of type consisting entirely of such lines.
c. a thin rule for printing fine lines.
d. undesirable vertical lines between letters, caused by worn matrices.
—adj. narrow or fine as a hair: a hairline fracture.