Terms can never consist of any these five characters:
- Semicolon (;)
- Quotation mark (“)
- Angle brackets (< >)
- Pipe (|)
When using an ampersand (&) character in the term store they are automatically replaced with a variant of the ampersand character. In SharePoint this variant is always replaced with a regular ampersand so it renders nicely.
This rendered ampersand does however not work correctly when used in Quick Parts in Word. Keep this in mind when creating terms. Avoid it if possible.