bless: [OE] Bless occurs in no other language than English, and originally meant ‘mark with blood’, from some sort of religious rite in which such marking conferred sanctity. It probably goes back to a prehistoric Germanic formation *blōthisōjan, a derivative of *blōtham ‘blood’, which was taken up by no Germanic language other than Old English. Here it produced blētsian, which by the 13th century had become blesse. The word’s connotations of ‘happiness’ and ‘well-being’, which go back at least to the year 1000, were probably influenced by the etymologically unrelated bliss. => blood
bless (v.)
Old English bletsian, bledsian, Northumbrian bloedsian "to consecrate, make holy, give thanks," from Proto-Germanic *blodison "hallow with blood, mark with blood," from *blotham "blood" (see blood (n.)). Originally a blood sprinkling on pagan altars. This word was chosen in Old English bibles to translate Latin benedicere and Greek eulogein, both of which have a ground sense of "to speak well of, to praise," but were used in Scripture to translate Hebrew brk "to bend (the knee), worship, praise, invoke blessings." L.R. Palmer ("The Latin Language") writes, "There is nothing surprising in the semantic development of a word denoting originally a special ritual act into the more generalized meanings to 'sacrifice,' 'worship,' 'bless,'" and compares Latin immolare (see immolate). Meaning shifted in late Old English toward "pronounce or make happy," by resemblance to unrelated bliss. No cognates in other languages. Related: Blessed; blessing.