Aerial (Antenna) A device to receive or transmit radio signals. It is also known as an antenna.
The diagram shows a simple circuit of a battery, wires, a switch and a lamp. The switch works by breaking the circuit.
Transistor PNP A transistor amplifies current and can be used with other components to make an amplifier or switching circuit. This symbol is for a bipolar junction transistor (BJT), the type you are most likely to use at first.
Voltmeter Measures voltage. The proper name for voltage is potential difference but voltage is more widely used.