allotrope

Etymology

Back-formation from allotropy, as allo- + -trope, from Ancient Greek ἄλλος (állos, “other”), and τρόπος (trópos, “way, manner”).

noun

1. (chemistry) Any form of an element that has a distinctly different molecular structure to another form of the same element, with different physical properties and often different chemical properties.
   Ozone (O₃) is an allotrope of oxygen, normally O₂ Note: Different structural forms of a compound are isomers.
2. (linguistics) An other form, a different shape of a lexical unit.
3. (philosophy) An alternative shape of a cognitive structure.