projective plane
Mathematics
noun
A two-dimensional manifold which may be regarded as the space of straight lines through the origin of three-dimensional space, or as a spherical shell with all pairs of antipodal points identified (each straight line through the sphere's centre projecting two antipodal points at which it intersects the spherical shell on to a single point of the plane).
Origin
Late 19th century; earliest use found in Science.
- the knives are out (for someone)
- the Kop
- the Kremlin
- the Kurils
- the ladies
- the Lakes
- the Lamb of God (also the Lamb)
- the land of Nod
- the land of the free
- the last minute
- the last (or final) straw
- the last straw
- the last word
- the laugh is on me (or you, him, etc.)
- the Law
- (the law of) diminishing returns
- the Law of Moses
- the law of the jungle
- the Left
- the length and breadth of
- the lesser evil (or the lesser of two evils)
- the Lido
- the lie (lay) of the land
- the life and soul of the party (the life of the party)
- the light of day