Abstract nonsense

Abstract nonsense(Q1084766) is likely coin-phrased by Norman Steenrod, referring to Category Theory. On the math glossary website: Math Vault, abstract nonsense is defined as follows:

A colloquial term for category theory (a mathematical subject dedicated to the notion of category and the formalization of mathematical structures), or the methods and arguments that are related to it. ... “general abstract nonsense” or “generalized abstract nonsense“.