Noun
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 dictionaryThe latus rectum is the line segment within the curve (solid yellow). Source: Internet
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. Source: Internet
The measurements shown on the above diagram are in units of the latus rectum, which is four times the focal length. Source: Internet
The point where the slope of the parabola is 1 lies at one end of the latus rectum. Source: Internet