The ratio of image to object size in an optical system. may be real (linear) or apparent (angular). milliradian (mrad)1/1000th of a radian, or 0.0573 degrees; the angle whose tangent is 0.001.
The increase in the apparent or perceived size or subtended angle of an image in relation to actual size of object.
Увеличение ~ of lens увеличение лупы
The power of a microscope (or lens) to produce an image that appears larger than the actual specimen, expressed as a factor of the actual size