Formalin.
An evening gown.
An event with a formal dress code.
Jenny took Sam to her Year 12 formal.
A formal parameter.
Being in accord with established forms.
She spoke formal English, without any dialect.
Official.
I'd like to make a formal complaint.
Relating to the form or structure of something.
Formal linguistics ignores the vocabulary of languages and focuses solely on their grammar.
Relating to formation.
The formal stage is a critical part of any child's development.
Ceremonial or traditional.
Formal wear must be worn at my wedding!
Proper, according to strict etiquette; not casual.
He's always very formal, and I wish he'd relax a bit.
Organized; well-structured and planned.
When they became a formal club the rowers built a small boathouse.
Relating to mere manipulation and construction of strings of symbols, without regard to their meaning.
Formal series are defined without any reference to convergence.