The generic term for a pattern that repeats over time is a wave - sound waves, brain waves, ocean waves, and voltage waves are all repeating patterns. An oscilloscope measures voltage waves. One cycle of a wave is the portion of the wave that repeats. A waveform is a graphic representation of a wave. A voltage waveform shows time on the horizontal axis and voltage on the vertical axis.
Waveform shapes tell you a great deal about a signal. Any time you see a change in the height of the waveform, you know the voltage has changed. Any time there is a flat horizontal line, you know that there is no change for that length of time. Straight diagonal lines mean a linear change - rise or fall of voltage at a steady rate. Sharp angles on a waveform mean sudden change. Figure shows below common waveforms and Next figure shows some common sources of waveforms.
Oscilloscope Common Waveforms
Oscilloscope Sources of Common Waveforms.