Obs. [L., neut. of expansus, pa. pple. of expandĕre to EXPAND. Adopted by scholars of 1617th c. as lit. rendering of Heb. rāqīas (Vulg. firmamentum, AV. firmament).] = EXPANSE sb.
1635. Swan, Spec. M., iv. § 1 (1643), 54. The Expansum, or stretching out of the Heavens.
1640. Wilkins, New Planet, II. (1684), 39. The common People usually think the Rain to proceed from some Waters in the Expansum.
1651. Jer. Taylor, Serm. for Year, I. xxv. 314. The mercy of God [is] a vast expansum and a huge Ocean.
1794. R. J. Sulivan, View Nat., II. 403. Till the whole expansum was cleared of these gross and opaque parts of matter.