radio · noun /ˈreɪd.iːˌoʊ/
radio (EQUIPMENT)
A1 C a piece of equipment used for listening to sound broadcasts
Dictionary examples:
a car radio
Could you turn the radio on?
Learner example:
I want to sell my radio. (Key English Test; A2; Italian)
the radio
A1 the programs that you hear when you listen to the radio
Dictionary examples:
We heard him talking on the radio this morning.
I listen to the radio in the morning.
Learner example:
He likes watching television and listening [to the] radio. (Skills for Life (Entry 1); A1; Polish)
radio (SYSTEM)
B1 U a system of sending and receiving sound through the air
Dictionary examples:
local radio
a radio station
Learner example:
I'm thinking [of] call[ing] the radio station to inform [them about] my situation. (Preliminary English Test; B1; Portuguese)