Austenite

a solid solution of carbon or of carbon and other elements in gamma iron, having a face-centered cubic lattice at all temperatures.
an allotrope of iron, stable between 910°C and 1400°C and having a face-centered cubic lattice; gamma iron.
Historical Examples

The first particles of austenite to freeze contain about 0.33% of carbon (p).
Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 7 Various

Ferrite and cementite, already described in 10, are the final products of the transformation of austenite in slow-cooling.
Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 7 Various

The white-hot, solid, but soft mass is now a conglomerate of “primary” austenite, “eutectic” austenite and “eutectic” cementite.
Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 7 Various

austenite may contain carbon in any proportion up to about 2.2%.
Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 7 Various

noun
a solid solution of carbon in face-centred-cubic gamma iron, usually existing above 723°C
the gamma phase of iron, stabilized at low temperatures by the addition of such elements as nickel