firm, solid, strong
circular, flat, rounded, square
concrete, granite, steel, etc.

have
The statue has a solid concrete base.

firm, secure, solid, sound, strong
economic, evidence, ideological, scientific
His arguments have a sound economic base.

form, have
establish, give sb, provide (sb with)
These policies give us a solid base for winning the next election.

use sth as

base for
He used the notes as a base for his lecture.

solid, sound
broad, narrow
These policies have a broad base of support.

power
a politician with a rural power base

democratic
asset, commercial, economic, financial, industrial, manufacturing, political, resource, revenue, tax
The country has a sound commercial base.

client, customer, subscriber, user

create, form, have, provide
broaden, develop, expand, improve, increase
The company is trying to expand its customer base.

maintain

grow
shrink

excellent, ideal, perfect

have
The company has its base in New York.

establish, set up
The company has set up its new base in the north.

camp

base for
an ideal base for mountain expeditions

foreign
Demonstrators demanded the removal of foreign bases.

air, air-force, military, missile, naval

have
build, establish
The Americans established a naval base on the island in the 1960s.

attack
destroy
defend
occupy

at a/the base
equipment kept at the base

on a/the base
people living on the air force base

to (the) base
The planes have all returned to base.