a horn for the radiation of acoustic or high-frequency electromagnetic waves, of which the cross-sectional area increases exponentially with the length
exponential horn in American English
noun
a loudspeaker horn with a cross-sectional area varying as a constant raised to an exponent proportional to the distance from the vertex
Word origin
[1925–30]This word is first recorded in the period 1925–30. Other words that entered Englishat around the same time include: buildup, chain reaction, reflex camera, runout, turnaround