Looking up...
Posez le livre dessus.
Put the book on top.
On or to the upper surface or part of something
Il a mis ses clés dessus.
He put his keys on top.
Often used with the preposition 'de' to indicate origin or derivation (e.g., 'de dessus' = from above).
In addition to, as well as
Je vais prendre ça, et dessus, un café.
I'll take that, and on top of that, a coffee.
In informal contexts, it can mean 'in addition to' or 'on top of that.'
In formal contexts, prefer 'au-dessus' or 'par-dessus' over 'dessus.' In informal speech, 'dessus' is common.
When used as a preposition, it typically requires the preposition 'de' (e.g., 'de dessus').
From Old French 'desus,' from Latin 'de super,' meaning 'from above.'
Can be used as an adverb or preposition depending on context. In formal writing, 'au-dessus' is often preferred.