consolidate

Bring together into a single whole or system.

“The town and county schools are being consolidated”

Form into a solid mass or whole.

“The mud had consolidated overnight”

Make firm or secure; strengthen.

“consolidate one's gains”

“consolidate one's hold on first place”

Make or form into a solid or hardened mass.

“consolidate fibers into boards”

Unite into one.

“The companies consolidated”