Why is the ninth month called September?
wavelength wave·length (wāv'lěngkth', -lěngth')
Symbol λ The distance between one peak or crest of a wave of light, heat, or other energy and the next corresponding peak or crest.
The distance between crests (or troughs) of a wave.
In agreement; in harmony; tune in: Her door's open, but we are not on the same wavelength/ We do now have a long-range plan. Everybody's on the same page (1962+)