Etymology Dictionary

AISLE,  the wing of a church.  (F.,—L.)   Spelt aisle in Gray's Elegy and by Addison; see Richardson.—F. aile, a wing; sometimes spelt aisle, as Cotgrave notices.   But the s is a meaningless insertion.—Lat. āla, a wing; the long a being due to contraction.  It is no doubt contracted from axla or axula, whence the dimin. axilla, a wing; see Cicero, Orat. 45. 153; Fick, i. 478.   The proper meaning of axula is rather 'shoulder-blade' or 'shoulder'; cf. G. achsel.   It is a diminutive of Lat. axis, a word borrowed by us from that language.   See Axis, and Axle.   (Max Müller quotes the passage from Cicero; see his Lectures, ii. 309, 8th ed.) [†]

ADDENDA

It appears, from the quotations made for the Phil. Soc. Dict., that the s in the E. aisle was suggested by the s in E. isle, and was introduced, curiously enough, independently of the s in the F. spelling aisle.   Both E. and F. spellings are various and complicated.   See Phil. Soc. Proceedings, June 18, 1880.