A central concept in Factor is that of a combinator, which is a word taking code as input.
Fundamental combinators
Dataflow combinators
Conditional combinators
Looping combinators
Compositional combinators
Short-circuit combinators
Smart combinators
Quotation construction utilities
Generalized shuffle words and combinators

More combinators are defined for working on data structures, such as Sequence combinators and Associative mapping combinators.

See also
Quotations