formal

Etymology 1

From Middle English formel, borrowed from Old French formel, from Latin fōrmālis, from fōrma (“form”); see form.

adj

1. Being in accord with established forms.
   She spoke formal English, without any dialect.
2. Official.
   I'd like to make a formal complaint.
   Despite efforts by limnologists and freshwater biologists to create a formal definition of “pond”, there is still no universal distinction between a “pond” and a “lake.”
3. Relating to the form or structure of something.
   Formal linguistics ignores the vocabulary of languages and focuses solely on their grammar.
   THE THREE DOMINANT FORMS IN METALSMITHING […] At present, there are but three basic volumetric forms dominating the work of metalsmiths, the spherical (usually in its most practical form, the domical), the cylindrical, and the cubical. […] The possibilities for further variations on them are all but exhausted, there being little chance to express new and unusual ideas within the framework of such limited choices. As a result, much of twentieth-century metalsmithing has relied on surface enrichment rather than formal development for its originality. 1978, Heikki Seppä, Form Emphasis for Metalsmiths, [Kent, Oh.]: Kent State University Press, page 1
4. Relating to formation.
   The formal stage is a critical part of any child's development.
5. Ceremonial or traditional.
   Formal wear must be worn at my wedding!
6. Proper, according to strict etiquette; not casual.
   He's always very formal, and I wish he'd relax a bit.
7. Organized; well-structured and planned.
   When they became a formal club the rowers built a small boathouse.
8. (mathematics) Relating to mere manipulation and construction of strings of symbols, without regard to their meaning.
   Formal series are defined without any reference to convergence.

noun

1. (clothing) An evening gown.
   Well, I open up the door / And much to my surprise / The girls were wearin' formals / And the boys were wearin' ties 1965, Shadow Morton (lyrics and music), “Sophisticated Boom Boom”, performed by The Shangri-Las
2. An event with a formal dress code.
   Jenny took Sam to her Year 12 formal.
3. (programming) A formal parameter.
4. (Oxbridge slang) Ellipsis of formal hall..

Etymology 2

See formo-.

noun

1. (uncountable) Formalin.
2. An acetal formed from formaldehyde.