Parfocal

1 definition found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Parfocal \Par*fo"cal\, a. [Pari- + focal.] (Opt.)
     With the lower focal points all in the same plane; -- said of
     sets of eyepieces so mounted that they may be interchanged
     without varying the focus of the instrument (as a microscope
     or telescope) with which they are used. "the convenience of a
     microscope with parfocal objective lenses"


     [Webster 1913 Suppl.] Parforn