"Small amplitude" refers to a motion or change that is not very big or noticeable. It means that something is happening, but it is happening in a small, gentle, or quiet way. Full definition
Large fluctuations in lower density parts of the Universe have an effect similar to that of smaller amplitude fluctuations in denser regions and the two can not be distinguished by observations of weak lensing. (sciencedaily.com)
Another highly idealized theory is a barotropic storm track which for small amplitude waves can be approximated by WKB theory (Lee 1995; Swanson et al. 1997). (link.springer.com)
For example, analytic solutions of «linear» differential equations that describe simple harmonic motions are only found in dynamical systems with small amplitudes, where non - linear terms are assumed to be negligible. (religion-online.org)