Allotropy vs. Allotroph

Allotropy and Allotroph Definitions
Allotropy
The existence of two or more crystalline or molecular structural forms of an element that have different chemical or physical attributes.
Allotroph
(rare) heterotroph
Allotropy
(chemistry) A property, exhibited by some elements, of existing in multiple forms with different atomic structures.
Allotropy
The phenomenon of an element existing in two or more physical forms