Definition of principal point in English:

principal point

noun ˌprɪnsɪpl ˈpɔɪnt

1Perspective. The point where the principal ray meets the picture plane.
2Optics. Each of the two points at which the optic axis of a lens intersects the principal planes.

Late 16th century (in an earlier sense). From principal + point. In sense 1 after Middle French principal poinct.

nounˌprɪnsɪpl ˈpɔɪnt

1Perspective. The point where the principal ray meets the picture plane.
2Optics. Each of the two points at which the optic axis of a lens intersects the principal planes.

Late 16th century (in an earlier sense). From principal + point. In sense 1 after Middle French principal poinct.

词汇	principal point
释义	Definition of principal point in English: principal point noun ˌprɪnsɪpl ˈpɔɪnt 1Perspective. The point where the principal ray meets the picture plane. 2Optics. Each of the two points at which the optic axis of a lens intersects the principal planes. Origin Late 16th century (in an earlier sense). From principal + point. In sense 1 after Middle French principal poinct. Definition of principal point in US English: principal point nounˌprɪnsɪpl ˈpɔɪnt 1Perspective. The point where the principal ray meets the picture plane. 2Optics. Each of the two points at which the optic axis of a lens intersects the principal planes. Origin Late 16th century (in an earlier sense). From principal + point. In sense 1 after Middle French principal poinct.
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