n.

the distance (measured in the direction of propagation) between two points in the same phase in consecutive cycles of a wave

a shared orientation leading to mutual understanding

"they are on the same wavelength"

Quantum detection at millimeter wavelengths
Three-Dimensional Invisibility Cloak at Optical Wavelengths
A three-dimensional photonic crystal operating at infrared wavelengths
Global mapping functions for the atmosphere delay at radio wavelengths
Atomic data for resonance absorption lines. I - Wavelengths longward of the Lyman limit
Full three-dimensional photonic bandgap crystals at near-infrared wavelengths
Two-dimensional photonic-bandgap structures operating at near-infrared wavelengths
CHIANTI - an atomic database for emission lines, Paper 4: Extension to X-ray Wavelengths
ChemInform Abstract: Full Three-Dimensional Photonic Bandgap Crystals at Near-Infrared Wavelengths
Heim, R. & Tsien, R. Y. Engineering green fluorescent protein for improved brightness, longer wavelengths and fluorescence energy tr...