An Etymological Dictionary of Astronomy and Astrophysics

A showery precipitation in the form of nearly spherical or irregular → pellets of ice having a diameter of up to 50 mm or more.
Hail is associated with → thunderstorm cells that have strong currents of rising air and relatively great → humidity content. Hail can only form in cumulonimbus clouds. Water droplets, after the formation,
freeze and begin to fall downward through the cloud, but the wind blows them back upward. As the droplets begin to fall back down again, they collect more water which also freezes, so the drop becomes bigger. Then the wind blows them back up again. This occurs several times, but eventually the frozen droplets become too big and heavy and fall as hail. See also → sleet.

Etymology (EN): From M.E. haghel, hayl; O.E. hægl, hagol; cf. O.H.G. hagal, Ger. Hagel “hail;” probably from PIE *haghlo- “pebble”;
cf. Gk. kakhlex “round pebble;” Pers. Lori hogela “(big) stone.”

Etymology (PE): Tagarg, from *takaraka, *tancaraka- “dense, condensed,” from Proto-Ir. base *tanc- “become narrow, dense, constrict,” cf. Pers. tanjidan, “to squeeze, → compress,” tang “narrow, constricted;” Shahmirzadi tāž/ti&#382d; Sariqoli tož/ti&#382d “to pull, drag;” Pashto tat “close, thick;” Skt. tanákti “it coagulates,” takrá- “buttermilk;” M.Irish techt “coagulated;” Lith. tánkus “thick;” PIE *tenk- “to twist together, become thick” (H. W. Bailey, 1979).