latus rectum
Noun
Meaning
The line drawn through a focus of a conic section parallel to the directrix and terminated both ways by the curve. It is the parameter of the principal axis. See Focus, and Parameter.
Source: Webster's dictionarySynonyms
Examples
The latus rectum is the line segment within the curve (solid yellow).
The length of the semilatus rectum (half of the latus rectum) is the difference between the x-coordinates of this point, which is considered as P in the above derivation of the coordinates of the focus, and of the focus itself.
The measurements shown on the above diagram are in units of the latus rectum, which is four times the focal length.
The point where the slope of the parabola is 1 lies at one end of the latus rectum.