aspheric
adjective
aspher·ic (ˌ)ā-ˈsfir-ik 
-ˈsfer-
variants or aspherical
(ˌ)ā-ˈsfir-i-kəl
-ˈsfer-
: departing slightly from the spherical form especially in order to correct for spherical aberration
an aspheric lens
Word History
First Known Use
1869, in the meaning defined above
Medical Definition
aspheric
adjective
aspher·ic (ˈ)ā-ˈsfi(ə)r-ik, -ˈsfer-
variants or aspherical
-i-kəl
: departing slightly from the spherical form especially in order to correct for spherical aberration
an aspheric lens