Amplitude

The amplitude of a signal is the height of the wave above or below a given reference point.

Frequency

Frequency is the number of times a signal makes a complete cycle within a given time frame.

Spectrum: The range of frequencies that a signal spans from minimum to maximum.

Bandwidth: The absolute value of the difference between the lowest and highest frequencies of a signal

Example:-
The average voice has a frequency range of roughly 300 Hz to 3100 Hz.

The spectrum would thus be 300 - 3100 Hz. 

The bandwidth would be 2800 Hz.

Phase

The phase of a signal is the position of the waveform relative to a given moment of time or relative to time zero. A change in phase can be any number of angles between 0 and 360 degrees. Phase changes often occur on common angles, such as 45, 90, 135, etc.