589ea459_All_About_Monads___HaskellWiki__Type_of_computation
[Monad] Error [Combination strategy for >>=] Failure records information describing the failure. Binding passes failure information on without executing the bound function, or uses successful values as input to the bound function. [Type of computation] 
Computations which can fail or throw exceptions
All About Monads - HaskellWiki
Type of computation