Organize

3 clues
Arrange.
Form a union
Arrange systematically
Similar answers:
Aagonizes
Agonize
Agonized
Agonizes
Alexmorgan
Americanize
Antagonize
Antagonized
Antagonizer
Argonorgan
Avianizes
Balkanizes
Barrelorgan
Barrelorgans
Beingrecognized
Bioorganism
Borga
Botanize
Calorgas
Canonize