If we take "Functions" as a baseline, then we have... Floating Functions / First class functions (thanks to comments for reminding): Functions that can be pass

If we take "Functions" as a baseline, then we have... Floating Functions / First class functions (thanks to comments for reminding): Functions that can be passed around as variables. e.g. All functions in Javascript are floating functions. function callback() { ... } // function assigned to a variable var x = callback; // function is an argument to another function doSomething(..., callback) Anonymous functions: functions with no name. // an anonymous function (function() { .... })() // anonymous function as an argument doSomething(..., function() { .... }) Lambda functions: A style of writing functions without a block, where the function and return value are expressed as one single expression without the usage of a block or explicit returns. employee => employee.name Closures: When a function references a variable outside its scope, and that "frees" the variable from its normal lifetime, thus creating a "closure" between the function and the now-free variable. function a() { var x = 1; return function() { // here a closure is created // now "x" outlives its lifetime and // becomes a free variable return x + 1; } }