Definition: What is an Oscilloscope
An oscilloscope, informally known as a scope or DSO (short for digital storage oscilloscope), is a type of electronic test instrument that allows the user to observe constantly varying voltages, a.k.a. an electronic signal.
Whereas a voltmeter or multimeter will measure a static or slow-changing voltage and display it to the user as a single value, an oscilloscope will measure a fast-changing voltage and display it to the user as a 2-dimensional graph on a screen. The observed waveform can then be analysed for such properties as amplitude, frequency, rise time, time interval, distortion and others.