amplitude
How large a signal's value swings -- the A in A\cos(\omega n+\phi), independent of frequency or phase.
A signal's amplitude is the size of its swing away from zero -- the peak value A in a sinusoid A\cos(\omega n+\phi), or more generally a measure of a signal's typical magnitude. Amplitude, frequency, and phase are the three independent knobs that fully describe a sinusoid.
See also
Point table
Graph settings
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