the distance (measured in the direction of propagation) between two points in the same phase in consecutive cycles of a wave
"The laser beam had an extremely short wavelength, allowing it to focus on microscopic details."
The length of a single cycle of a wave, as measured by the distance between one peak or trough of a wave and the next; it is often designated in physics as λ, and corresponds to the velocity of the wave divided by its frequency.
"The red light emitted by the laser has a longer wavelength than the blue light because its peaks are spaced further apart."
In plain English: Wavelength is the distance between two matching points on a wave, like from one peak to the next.
"They are on the same wavelength because they understand each other perfectly without needing to explain much."
Usage: Wavelength refers to the physical distance between consecutive peaks or troughs of a wave. In everyday contexts, this term extends metaphorically to describe shared interests or attitudes among people who are compatible with each other.
This term combines the words wave and length, directly describing the physical distance between successive peaks of a wave. It entered English as a scientific phrase to measure this specific property without undergoing any major shift in meaning from its original construction.