1550s, from L. intersectionem (nom. intersectio) "a cutting asunder, intersection," from intersectus, pp. of intersecare "intersect, cut asunder," from inter- "between" + secare "to cut" (see section). Originally a term in geometry, meaning "crossroads" is from 1864.
The point or set of points where one line, surface, or solid crosses another.
The set that contains only those elements shared by two or more sets. The intersection of the sets {3,4,5,6} and {4,6,8,10} is the set {4,6}. The symbol for intersection is . Compare union.