(aviation, travel) (in a reservation system) The letter used to signify a particular fare level.

(martial arts) A division of competition used to match competitors against others of their own weight

(linguistics) A linguistic form class whose members are words.

(US, colloquial) An introductory university course that is designed to "weed out" those students who are not able to pass it.

(algebra) A subset of a group which is an equivalence class in the quotient set of the group divided by conjugation as equivalence relation.

plural of weeder class

(mathematics, topology, geometry) Any of a group of characteristic classes associated with complex vector bundles, with applications in physics, string theory, etc.

plural of Chern class

plural of word class

Alternative form of subclass