Notional vs Notational - What's the difference?

As adjectives the difference between notional and notational

is that notional is of, containing, or being a notion; mental or imaginary while notational is of or pertaining to notation.

(en adjective)

Of, containing, or being a notion; mental or imaginary.

Speculative, theoretical, not the result of research.

This paper proposes a notional Federated Identity Management (FIM) architecture.

(linguistics) Having descriptive value as opposed to a syntactic category.

(finance) (Used to indicate an estimate or a reference amount)

* notionality * notionally

(en adjective)

Of or pertaining to notation

* notationality * notationally