Functionalism is the principle that architects should direct their efforts towards the function of buildings, and even define architectural beauty as a product of a functional solution. Sometimes this has been explained as a simplification of the Vitruvian triad (beauty, commodity and firmness) to eliminate beauty as an autonomous quality of architecture. In general this resulted in the abandoning of "superficial" ornament in architecture and is associated with the 20th century Modern Movement in architecture.

Franco-Swiss architect Le Corbusier said "a house is a machine for living in"

References

Link to Quote

Behne, Adolf (1923). The Modern Functional Building. Michael Robinson, trans. Santa Monica: Getty Research Institute, 1996.

Forty, Adrian. "Function". Words and Buildings, A Vocabulary of Modern Architecture. Thames & Hudson, 2000, p. 174-195.