From Longman Dictionary of Contemporary Englishhailstonehail‧stone, hail stone /ˈheɪlstəʊn $ -stoʊn/ noun [countable] DNa small ball of frozen rain
Examples from the Corpus
hailstone• And in 1958, a Sussex storm delivered a 5oz hailstone, Britain's heaviest ever.• One great big hailstone, right?• I found a small but perfectly-formed hailstone on my knee, which must have got in through the air vent.• In this way, the children became spread out instead of all clustering together with the coins descending on them like hailstones.• He and Jimmy lay beneath the wagon as a barrage of hailstones beat hard on the planks above. 