emergency
humanitarian
cash (esp. BrE), development, economic, financial, food, legal, medical, military, reconstruction, relief
Legal aid is a fundamental part of our system of justice.

federal, government, state
foreign, international, overseas
The country relies on foreign aid.

appeal for, call for
The country's president has appealed for international aid in the wake of the disaster.

extend, give (sb), provide (sb with), send (sb)
get, receive
depend on, rely on
promise
cut, cut off, suspend, withdraw, withhold
The government has now suspended humanitarian aid to the area.

agency, worker
budget, package, programme/program
a $240 million aid package

ask for, enlist
We enlisted the aid of John and his family.

come to sb's, go to sb's (= to help someone)
She screamed loudly and two people came to her aid.

in aid of (esp. BrE)
We were collecting money in aid of charity.

with the aid of, without the aid of
She is now able to get around with the aid of a walking stick.

effective, essential, useful, valuable
teaching, training, visual
hearing, walking (BrE)
memory
navigational
sleep (AmE)
buoyancy (BrE)

aid to
Dictionaries are essential aids to learning.