:Boundary tone:

A tone associated with an intonational boundary as opposed to those associated with accented syllables. Boundary tones may be associated to the initial or final boundaries of intermediate phrases (symbols L- and H-) or intonational phrases (symbols L% and H%). The concept is particularly associated with Pierrehumbert’s analysis of intonation. An example: a fall-rise tone would be represented as a H* pitch accent, followed by a L- intermediate phrase boundary tone and a H% intonational phrase boundary tone.

Also called edge tone.

Pierrehumbert J. (1980) The phonology and phonetics of English intonation. Bloomington: Indiana University Press.