Formerly hyphenated words split in two: fig leaf, hobby horse, ice cream, pin money, pot belly, test tube, water bed."Ice cream" used to be hyphenated? Really? Was this a British thing? Even the New Yorker isn't pretentious enough to hyphenate "ice-cream," is it?
Formerly hyphenated words unified in one: bumblebee, chickpea, crybaby, leapfrog, logjam, lowlife, pigeonhole, touchline, waterborne.