Conjunction (3)
(Other definitions for but that I've seen before include "Save" , "Only in attribution" , "Only; apart from" , "Except; nevertheless" , "Nevertheless, on the other hand" .)
'conjunction' is the definition.
('and' is a conjunction)
This is all the clue.
(Other definitions for and that I've seen before include "In addition" , "Word to connect" , "moreover" , "A very common conjunction" , "See 20" .)
'conjunction' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for union that I've seen before include "Equity is one" , "(Pipe) coupling" , "Group who may want better conditions" , "workers' co-operative" , "A joining together as in marriage" .)