cupping (n.)

A term sometimes used in PHONETICS for one of the transverse ARTICULATIONS which may be made by the TONGUE: specifically, it refers to the way the tongue body is able to adopt a concave, hollowed shape during an articulation, by allowing the mid-line of the tongue to drop lower than the sides. The effect is common in the formation of RETROFLEX consonants. A contrast can be drawn with GROOVING.