English
all-party
From all- + party.
Proto-Italic *partis ‘part’
…
Old French partir ‘to divide’
Old French partie ‘side’
Anglo-Norman partie
Middle English party
English party
first attested First attested in the 1900s (as stated in the etymology)
The story
First attested in the 1900s.
Today it means
adj Involving or relating to all political parties.
Language periods are conventional ranges, not dates for this word.
Etymograph / all-party