Crossword Genius

Posy suggesting one's head not all straight? (7)

Ross

I believe the answer is:

omnibus

I'm a little stuck... Click here to teach me more about this clue!

I believe this clue is a quintuple definition!!

'posy' is the first definition.
(thesaurus)

'suggesting' is a link.

'one's' is the second definition.
(thesaurus)

'head not' is the third definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I don't see?

'all' is the fourth definition.
(thesaurus)

'straight?' is the fifth definition.
(thesaurus)

Can you help me to learn more?

(Other definitions for omnibus that I've seen before include "Anthology" , "Large vehicle - collected edition" , "A number of books in one" , "Compound volume" , "Charabanc" .)

I've seen this clue in The Times.
Want a hint initially instead of a full solution? Install my app