a monoid in an endofunctor category

A monad is a monoid in an endofunctor category.

a design pattern that allows structuring programs generically while automating away boilerplate code needed by the program logic

In functional programming, a monad is a design pattern that allows structuring programs generically while automating away boilerplate code needed by the program logic.

a structure that represents computations

In programming, a monad is a structure that represents computations.

a design pattern concept used in mostly functional programming languages like lisp or in the modern world clojure or scala

A monad is a design pattern concept used in mostly functional programming languages like lisp or in the modern world clojure or scala.

an object in Scala which wraps another object

A Monad is an object in Scala which wraps another object.

a container type

*: 'A monad is a container type together with a few methods defined on a few methods .

an algebraic structure in category theory

A monad is an algebraic structure in category theory, and in Haskell it is used to describe computations as sequences of steps, and to handle side effects such as state and IO.

a certain type of context

Monads are conditional function calls' 'a monad is a certain type of context that provides two things: a way to put things into the context, and function application within the context' '...

a simple kind of error monad, where all errors are represented by Nothing

a monad is a simple kind of error monad, where all errors are represented by Nothing.

a design pattern that is useful in purely functional languages such as Haskell

Somewhere, somebody is going to hate me for saying this, but if I were to try to explain monads to a Java programmer unfamiliar with functional programming, I would say: 'Monad is a design pattern that is useful in purely functional languages such as Haskell.

a design pattern invented to address a shortcoming in 'pure' functional languages

FP practitioners may not realize this, but a monad is a design pattern invented to address a shortcoming in 'pure' functional languages.

a data type

A monad is a data type, and something that has a monadic type is a value.

a design pattern that defines how functions, actions, inputs, and outputs can be used together to build generic types, with the following organization

In functional programming, a monad is a design pattern that defines how functions, actions, inputs, and outputs can be used together to build generic types, with the following organization.

used in functional programming to sequence computation

A monad is an abstract concept used in functional programming to sequence computation, but computationcan also be useful in OOP.

a pattern for doing function composition with ‘amplified’ types

I won’t go into the details of explaining monads, but in essence a monad is a pattern for doing function composition with ‘amplified’ types (as Mike Hadlow puts ‘amplified’ types very eloquently on Mike Hadlow's blog series about monads).

a simple kind of error monad, where all errors are represented by None

a monad is a simple kind of error monad, where all errors are represented by None.

an object that encapsulates an operation

A Monad (besides the professorial definition you could find on the Internet) is an object that encapsulates an operation (in fact this definition is much more understandable for a programmer).

that can conceptually have external effects

A monad is a mathematical abstraction of an operation that can conceptually have external effects.

an 'independent' spiritual or divine entity

Strictly speaking, a monad is an 'independent' spiritual or divine entity in continuous evolution on continuous evolution's own plane; in other words, a relatively full-blown god.