from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Something that bisects, especially a ray that bisects an angle.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A line or curve that bisects or divides a line segment, angle, or other figure into two equal parts.
from the GNU version of the Collaborative International Dictionary of English
- n. One who, or that which, bisects; esp. (Geom.) a straight line which bisects an angle.
from The Century Dictionary and Cyclopedia
- n. A line drawn through the vertex of a triangle so as to bisect either the opposite side (bisector of the side) or the angle (bisector of the angle, or internal bisector), or to bisect the external angle formed by the adjacent sides (external bisector).
bisect + -or (Wiktionary)