notional

Short definition from Wiktionary

Adjective

1. 1
   Of, containing, or being a notion; mental or imaginary.
2. 2
   Speculative, theoretical, not the result of research.
3. 3
   Stubborn.
4. 4
   Having descriptive value as opposed to a syntactic category.
5. 5
   Used to indicate an estimate or a reference amount
6. 6
   Full of ideas or imaginings.

Noun

1. 1
   A fake company used as a front in espionage.