the skull of a human being," "early 15c., craneum, from Medieval Latin cranium "skull," from Greek kranion "skull, upper part of the head," related to kara (poetic kras) "head," from PIE root *ker- (1) "horn; head." Strictly, the "brain-box," the bony case which encloses the brain. Englished by Sir Thomas Browne as crany.
Old English caru, cearu "sorrow, anxiety, grief," also "burdens of mind; serious mental attention," in late Old English also "concern, anxiety caused by apprehension of evil or the weight of many burdens," from Proto-Germanic *karō "lament; grief, care" (source also of Old Saxon kara "sorrow;" Old High German chara "wail, lament;" Gothic kara "sorrow, trouble, care;" German Karfreitag "Good Friday;" see care (v.)).
Meaning "charge, oversight, attention or heed with a view to safety or protection" is attested from c. 1400; this is the sense in care of in addressing (1840). Meaning "object or matter of concern" is from 1580s. To take care of "take in hand, do" is from 1580s; take care "be careful" also is from 1580s.
The primary sense is that of inward grief, and the word is not connected, either in sense or form, with L. cura, care, of which the primary sense is pains or trouble bestowed upon something. [Century Dictionary]
Old English hergian "make war, lay waste, ravage, plunder," the word used in the Anglo-Saxon Chronicle for what the Vikings did to England, from Proto-Germanic *harjon (source also of Old Frisian urheria "lay waste, ravage, plunder," Old Norse herja "to make a raid, to plunder," Old Saxon and Old High German herion, German verheeren "to destroy, lay waste, devastate"). This is literally "to overrun with an army," from Proto-Germanic *harjan "an armed force" (source also of Old English here, Old Norse herr "crowd, great number; army, troop," Old Saxon and Old Frisian heri, Dutch heir, Old High German har, German Heer, Gothic harjis "a host, army").
The Germanic words come from PIE root *korio- "war" also "war-band, host, army" (source also of Lithuanian karas "war, quarrel," karias "host, army;" Old Church Slavonic kara "strife;" Middle Irish cuire "troop;" Old Persian kara "host, people, army;" Greek koiranos "ruler, leader, commander"). Weakened sense of "worry, goad, harass" is from c. 1400. Related: Harried; harrying.
c. 1200, "the face, countenance," especially as expressing emotion, from Anglo-French chere "the face," Old French chiere "face, countenance, look, expression," from Late Latin cara "face" (source also of Spanish cara), possibly from Greek kara "head," from PIE root *ker- (1) "horn; head." From mid-13c. as "frame of mind, state of feeling, spirit; mood, humor."
By late 14c. the meaning had extended metaphorically to "state or temper of mind as indicated by expression." This could be in a good or bad sense ("The feend ... beguiled her with treacherye, and brought her into a dreerye cheere," "Merline," c. 1500), but a positive sense, "state of gladness or joy" (probably short for good cheer), has predominated since c. 1400.
Meaning "that which makes cheerful or promotes good spirits" is from late 14c. Meaning "shout of encouragement" is first recorded 1720, perhaps nautical slang (compare earlier verbal sense, "to encourage by words or deeds," early 15c.). The antique English greeting what cheer? (mid-15c.) was picked up by Algonquian Indians of southern New England from the Puritans and spread in Indian languages as far as Canada.