An Etymological Dictionary of Astronomy and Astrophysics

An → aberration of a → lens  → system in which → magnification increases with → distance from the → optical axis, whereby → horizontal and → vertical lines bend inward toward the → center of the → field. Opposite of → barrel distortion.

Etymology (EN): Pincushion, from pin, from M.E. pinne, O.E. pinn “peg;” cf. D. pin, Ger. Pinne; perhaps from L. pinna “feather, quill”

• cushion, M.E. cuisshin, O.Fr. coissin (Fr. coussin) a variant of V.L. *coxinum, either from L. coxa “hip, thigh,” or from L. culcita “mattress;” → distortion.

Etymology (PE): Cowlegi, → distortion; bâleštaki, adj. of bâleštak, diminutive of bâlešt, variant bâleš “cushion, pillow,”
Mid.Pers. bâlišn, bâlên “cushion, pillow;”
Av. barəiš- “pillow, cushion;” cf. Skt. barhis- “straw, a bed or layer of kusa grass strewed over the sacrificial ground.”