diaphone

noun

1. a foghorn producing a low-pitched, penetrating signal of two tones.
2. Phonetics.
   1. a phoneme in one dialect corresponding to a similar but phonetically different phoneme in a related dialect.
   2. a group of sounds comprising all the phonetically different dialectal variants of a given phoneme in a language: The broad a and flat a of “half” are members of a single diaphone.

noun

1. 1. the set of all realizations of a given phoneme in a language
   2. one of any number of corresponding sounds in different dialects of a language
2. a foghorn that emits a two-toned signal