Old English hælþ "wholeness, a being whole, sound or well," from Proto-Germanic *hailitho, from PIE *kailo- "whole, uninjured, of good omen" (source also of Old English hal "hale, whole;" Old Norse heill "healthy;" Old English halig, Old Norse helge "holy, sacred;" Old English hælan "to heal"). With Proto-Germanic abstract noun suffix *-itho (see -th (2)).
Of physical health in Middle English, but also "prosperity, happiness, welfare; preservation, safety." An abstract noun to whole, not to heal. Meaning "a salutation" (in a toast, etc.) wishing one welfare or prosperity is from 1590s. Health food is from 1848.
Old English halgian "to make holy, sanctify; to honor as holy, consecrate, ordain," related to halig "holy," from Proto-Germanic *hailagon (source also of Old Saxon helagon, Middle Dutch heligen, Old Norse helga), from PIE root *kailo- "whole, uninjured, of good omen" (see health). Used in Christian translations to render Latin sanctificare. Related: Hallowed; hallowing.
It is wrong to say that certain articles of food are healthy or unhealthy. Wholesome and unwholesome are the right words. A pig may be healthy or unhealthy while alive; but after he is killed and becomes pork, he can enjoy no health, and suffer no sickness. [Eliza Leslie, "Miss Leslie's Behaviour Book," Philadelphia, 1839]
Healthsome is from 1530s in the sense "bestowing health."
Old English hælan "cure; save; make whole, sound and well," from Proto-Germanic *hailjan (source also of Old Saxon helian, Old Norse heila, Old Frisian hela, Dutch helen, German heilen, Gothic ga-hailjan "to heal, cure"), literally "to make whole" (from PIE *kailo- "whole;" see health). Intransitive sense from late 14c. Related: Healed; healing.
salutation in greeting, c. 1200, from Old Norse heill "health, prosperity, good luck," or a similar Scandinavian source, and in part from Old English shortening of wæs hæil "be healthy" (see health; and compare wassail).
The interj. hail is thus an abbreviated sentence expressing a wish, 'be whole,' i. e., be in good health, and equiv. to L. salve, plural salvete, or ave, plural avete .... [Century Dictionary]
"in good health, robust," Old English hal "healthy, sound, safe; entire; uninjured; genuine, straightforward," from Proto-Germanic *hailaz(source also of Old Frisian hel"complete, full; firm" (of ground), Old High German heil, Old Norse heill "hale, sound," Gothic hails "hale"), from PIE *kailo- "whole, uninjured, of good omen" (see health). The Scottish and northern English form of whole and with a more etymological spelling. It later acquired a literary sense of "free from infirmity" (1734), especially in reference to the aged. Related: Haleness.
mid-12c., from Old Norse ves heill "be healthy," a salutation, from ves, imperative of vesa "to be" (see was) + heill "healthy," from Proto-Germanic *haila- (see health). Use as a drinking phrase appears to have arisen among Danes in England and spread to native inhabitants.
A similar formation appears in Old English wes þu hal, but this is not recorded as a drinking salutation. Sense extended c. 1300 to "liquor in which healths were drunk," especially spiced ale used in Christmas Eve celebrations. Meaning "a carousal, reveling" first attested c. 1600. Wassailing "custom of going caroling house to house at Christmas time" is recorded from 1742.