An aerial for receiving or transmitting radio signals is called an antenna. “Aerial” is the traditional British term, while “antenna” is the standard term in American English and in modern radio engineering.
An antenna converts electrical energy into electromagnetic radio waves when transmitting. When receiving, it performs the reverse process: it captures energy from incoming radio waves and produces a small electrical signal that a receiver can process. Antennas appear in many forms, including telescoping rods, wire antennas, loops, dishes, and the printed structures inside phones and wireless devices.
The best antenna design depends on the signal’s frequency, direction, polarization, and intended range. A half-wave dipole, for example, is roughly half a wavelength long and is a classic radio-antenna design. A satellite dish is also an antenna, but its reflector focuses incoming or outgoing microwave signals.
A common mistake is treating “aerial” and “antenna” as different devices. In this context, they are synonyms.