from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adjective of a chemical compound having a ring with four members
Sorry, no etymologies found.
Others were equally sure it was a four-membered ring fused to a five-membered ring, known as a beta lactam.
The double door frame projects pilaster-like, with a four-membered cornice above, from which rises an elliptical arch, with an elliptical cornice about a foot above.
OXE has an unstable chemical structure (a four-membered ring containing three carbons and one oxygen) that makes it prone to being split open.
Here it is easy to see the chemical structure, a four-membered ß-lactam ring attached to a six-membered sulphur-containing ring -- derived most probably like the corresponding penicillin, from "� - (a-aminoadipoyl) - cysteinyl valine but in an oxidized form.