formal

adj

1. In accordance 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.”

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. (especially)In accordance with a methodological framework with well-defined rules or laws; rigorous.

   “A set of words can be formal cognates only if they can be derived from a common ancestor by regular sound laws.”

   “Only formal proofs, which derive theorems logically from their given axioms, are considered satisfactory in modern mathematics.”

9. 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. (countable, uncountable)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”

2. (countable, uncountable)An event with a formal dress code.

   “Jenny took Sam to her Year 12 formal.”

3. (countable, uncountable)A formal parameter.
4. (abbreviation, alt-of, countable, ellipsis, uncountable)Ellipsis of formal hall.
5. (uncountable)Formalin.
6. (countable, uncountable)An acetal formed from formaldehyde.