Definition of "æquilateral"

In the firſt Courſe there was a Shoulder of Mutton, cut into an Æquilateral Triangle, a Piece of Beef into a Rhomboides, and a Pudding into a Cycloid.

1726 October 28, [Jonathan Swift], “The Humours and Dispositions of the Laputians Described. […]”, in Travels into Several Remote Nations of the World. […] [Gulliver’s Travels], volume II, London: […] Benj[amin] Motte, […], part III (A Voyage to Laputa, Balnibarbi, Glubbdubdribb, Luggnagg, and Japan), page 20