Waveform

According to an English dictionary a waveform is a usually graphic representation of the shape of a wave that indicates its characteristics (as frequency and amplitude).

A waveform is a representation of how alternating current (AC) varies with time, e.g., sine wave. The sine wave represents energy entirely concentrated at a single frequency. An ideal, unmodulated wireless signal has a sine waveform, with a frequency usually measured in megahertz (MHz) or gigahertz (GHz). 

A wave is a pattern of varying quantitative values that repeats over a certain interval of time. They are a periodically repeating phenomena. Signal generators produce electrical (voltage) waves that repeat in a controllable manner. A full repetition of a wave is called a cycle. Waveform graphically represents the activity of the wave and any change in it overtime. Some of the characteristics of waveforms are Amplitude, Frequency, and Phase. Amplitude of a wave measures the strength of the wave from the lowest point that a wave hits to the highest point. In other words it is the maximum disturbance (of a wave) from its undisturbed position. Frequency is the rate at which waveform cycles occur while phase is the time placement of a cycle relative to a reference waveform or point in time.