## Wikipedia - Eutectic system (en) peritectoid reaction

Synonym: metatectoid reaction
https://doi.org/10.1351/goldbook.P04501
An isothermal, reversible reaction in the solid state, that, on cooling of a binary, ternary, ... , $$n$$ system, results in one, two, ... ($$n-1$$) new solid phases. For example, in a binary system containing two solids $$\alpha'$$ and $$\alpha''$$ $\alpha' + \alpha'' \rightarrow \beta$ Synonymous with metatectoid reaction.
Source:
PAC, 1994, 66, 577. (Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)) on page 588 [Terms] [Paper]