--- title: Haskell Glossary author: Michael Snoyman description: Define commonly used but not-commonly-understood terms first-written: 2015-02-24 last-updated: 2015-02-24 last-reviewed: 2015-02-24 --- This is a simple glossary of terms. It can cover technical terms, mathematical terms, tooling terms, and even general programming terms. Please feel free to make any additions desired without checking with the author! Try to keep everything in alphabetical order. * __Catamorphism__ * __Contravaraint__: see [covariance and contravariance](covariance-contravariance.md) * __Covariant__: see [covariance and contravariance](covariance-contravariance.md) * __Negative position__: see [covariance and contravariance](covariance-contravariance.md) * __Positive position__: see [covariance and contravariance](covariance-contravariance.md)