het·er·o·dyne 
(hĕtər-ə-dīn′)
(hĕtər-ə-dīn′)adj.
Having alternating currents of two different frequencies that are combined to produce two new frequencies, the sum and difference of the original frequencies, either of which may be used in radio or television receivers by proper tuning or filtering.
tr.v. het·er·o·dyned, het·er·o·dyn·ing, het·er·o·dynes
To combine (a radio-frequency wave) with a locally generated wave of different frequency in order to produce a new frequency equal to the sum or difference of the two.
[HETERO- + -dyne, power, frequency (from Greek dunamis, power; see DYNAMIC).]