The Collaborative International Dictionary
Amasthenic
Amasthenic \Am`as*then"ic\, a. [Gr. ? together + ? force.] (Photog.) Uniting the chemical rays of light into one focus, as a certain kind of lens; amacratic.
Wiktionary
amasthenic
a. (context photography English) Uniting the rays of light into one focus, as a certain kind of lens does.