An informal unit of volume popularized recently by Rachael Ray on her television shows in the U.S. Ray uses the palmful to mean a tablespoon (15 milliliters)
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}