Word Study
anastigmat
CIDE DICTIONARY
anastigmat, n.
compound lens or lens system designed to be free of astigmatism and able to form approximately point images. [WordNet 1.5]
OXFORD DICTIONARY
anastigmat, n. a lens or lens-system made free from astigmatism by correction.
Etymology
G f. anastigmatisch ANASTIGMATIC
For further exploring for "anastigmat" in Webster Dictionary Online