Ampelius, Aide-mémoire 1.1-2

mundus est universitas rerum, in quo omnia sunt et extra quem nihil; qui Graece dicitur κόσμος. elementa mundi quattuor: ignis ex quo est caelum, aqua ex qua mare Oceanum, aer ex quo venti et tempestates, terra quam propter formam eius orbem terrarum appellamus.

The universe is the entirety of things, in which are all things and outside of which is nothing. In Greek it is called the ‘cosmos’. There are four elements in the world: fire, of which the sky is made; water, of which the sea Ocean is made; air, of which winds and tempests are made; and earth, which on account of its shape we call the ‘circle of the lands’.