The American Heritage® Dictionary of the English Language, 4th Edition
n. A trill consisting of alternation between a written note and the note immediately above it. Also called inverted mordent.
the GNU version of the Collaborative International Dictionary of English
n. A melodic embellishment consisting of the quick alternation of a principal tone with an auxiliary tone above it, usually the next of the scale; -- called also the inverted mordente.
The Century Dictionary and Cyclopedia
n. The German name for the inverted mordent 01 passing trill (which see, under trill).
Word Usage
"The American College Dictionary defines a pralltriller as "an inverted mordent.""