formalise

verb5

1. •
   To give something a formal or official standing.
2. •
   To give something a definite form; to shape.
3. •
   To develop into a definite form.

   • We have more fun and exciting fundraisers planned, and we're trying to carefully budget them so they don't cut into your life savings. As they formalize, we'll widely publicize these events. — 1984
4. •
   To rigorously prove a mathematical result.
5. •
   To act with formality.