wave theory

WordReference Random House Unabridged Dictionary of American English © 2026

wave′ the′ory, 

1. Physics Also called undulatory theory. the theory that light is transmitted as a wave, similar to oscillations in magnetic and electric fields. Cf. corpuscular theory. 
2. Linguistics [Historical Ling.] a theory that accounts for shared features among languages or dialects by identifying these features as innovations that spread from their points of origin to the speech of contiguous areas. Cf. family-tree theory. 
• 1825–35

Collins Concise English Dictionary © HarperCollins Publishers::

wave theory noun

1. the theory proposed by Huygens that light is transmitted by waves
2. any theory that light or other radiation is transmitted as waves
   See electromagnetic wave

Compare corpuscular theory