from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The existence, especially in the solid state, of two or more crystalline or molecular structural forms of an element.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A property, exhibited by some elements of existing in multiple forms with different atomic structures.
from The Century Dictionary and Cyclopedia
- n. The property which certain chemical elements have of existing in two or more distinct forms, each having certain characteristics peculiar to itself.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the phenomenon of an element existing in two or more physical forms
allo- + -tropy (Wiktionary)