|A) line segment||B) vertex|
|C) focus||D) major axis|
As parabola is a locus of a point, which moves so that its distance from focus and directrix is always equal.
The latus rectum of a conic section is the chord (line segment) that passes through the focus, is perpendicular to the major axis and has both endpoints on the curve. The length of the latus rectum is determined differently for each conic.
The length of a parabola's latus rectum is 4p, where p is the distance from the focus to the vertex.