What is "khagne"

The literary and humanities "classe préparatoire aux grandes écoles" (CPGE) or "classe prépa"" is a two-year-long program after secondary school graduation, baccalauréat. Its mission is to prepare undergraduate students for the competitive entrance examination to the three Écoles normales supérieures (ENS), but also to the École nationale des chartes, to business schools or to Instituts d'études politiques. "Khâgne" informally refers to the literary and humanities CPGE. But more precisely, the term refers to the second year of the program, also known as "Première Supérieure", while the first year is known as "Lettres Supérieures" or "hypokhâgne" (from Greek hypo, "under").