Hail n. : Small roundish masses of ice precipitated from the clouds, where they are formed by the congelation of vapor. The separate masses or grains are called hailstones.

Hail v. i. : To pour down particles of ice, or frozen vapors.

Hail v. t. : To pour forcibly down, as hail.

Hail a. : Healthy. See Hale (the preferable spelling).

Hail v. t. : To call loudly to, or after; to accost; to salute; to address.

Hail v. t. : To name; to designate; to call.

Hail v. i. : To declare, by hailing, the port from which a vessel sails or where she is registered; hence, to sail; to come; -- used with from; as, the steamer hails from New York.

Hail v. i. : To report as one's home or the place from whence one comes; to come; -- with from.

Hail v. t. : An exclamation of respectful or reverent salutation, or, occasionally, of familiar greeting.

Hail n. : A wish of health; a salutation; a loud call.

Example:
What causes the difference between Hail and snow?

Taxonomy
Hail, millimetres, hailstorms, hailstones, diameter, thunderstorms, updraft, ice, cloud, free encyclopedia, largest hailstone, Search, Hail size, radar data, Hail cannon, Hail Storm, Hail Reports, Hail, hail.

Defination from the web:
Hail is a form of precipitation which consists of balls or irregular lumps of ice (hailstones) ... The METAR code for hail 5 mm or greater in diameter is GR, while smaller hailstones and graupel are coded GS. ...