"mid" + hrif
"belly," from P.Gmc. *hrefiz-
(cf. O.H.G. href,
"belly"), from PIE *kwrep-
"body, form, appearance" (see corporeal
). More or less obsolete after 18c. except in phrase to tickle (one's) midriff
"to cause laughter," the word revived 1941 in fashion usage for "portion of a woman's garment that covers the belly, as a euphemistic avoidance of belly,
extended 1970 to a belly-baring style of women's top.