A Plain

1. An expanse of land with relatively low relief, usually exclusive of forests, deserts, and wastelands.
2. (archaic) Synonym of field in reference to a battlefield.
3. (obsolete) Alternative spelling of plane: a flat geometric field.

Usage notes

• As with grassland(s), flatland(s), &c., plains can function as the plural of plain (There are ten principal low plains on Mars) or as its synonym (She lives in the plains), with a vague sense of greater expansiveness.

Synonyms

• (flat land): plains, flatland, flatlands, grassland, grasslands