(law, chiefly US, Canada) A lawsuit brought by a single plaintiff or small group of plaintiffs as a representative of a large group of others having a common interest, with everyone in the large group eligible to receive damages if the plaintiff is successful.

those people at the top of a social hierarchy / the aristocracy

occupying a position between the upper class and the working class

(A status, section, etc which is of) premier rank. / (Ireland) the third year of primary school, following after the junior and senior infant levels.

Belonging to the best or top group in a system of classification. / Of, or relating to the most luxurious and expensive class of accommodation on a train, ship, hotel, etc.

A social and economic class lying above the working class and below the upper class.

The social class of those who perform physical work for a living, as opposed to the professional or middle class, the upper class, or others.

Alternative spelling of working-class

(music) An equivalence class of all pitches that are octaves apart, and which would be labeled by an integer, not a traditional letter name.

(music) An interval measured by the distance between its two pitch classes ordered so they are as close as possible.