rules — a principle or regulation governing conduct, action, procedure, arrangement, etc.: the rules of chess.
staffs — a group of persons, as employees, charged with carrying out the work of an establishment or executing some undertaking.
stakes — something that is wagered in a game, race, or contest.
staves — a composition of plaster and fibrous material used for a temporary finish and in ornamental work, as on exposition buildings.
stems — science, technology, engineering, and mathematics, considered as a group of academic or career fields (often used attributively): degree programs in STEM disciplines; teaching STEM in high school.
