Source: The ARCADE "Dictionary of Word Origins" by John Ayto "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." So now that it references bliss, let's continue on with another definition from the same source.
"bliss [OE] Despite its formal and semantic similarity, bliss has no connection with bless. It comes ultimately from Germanic *blīthiz 'gentle, kind,' which is the source of English blithe 'happy' [OE]. The addition of the noun suffix *-tjō produced the derivative *blīthsjō, which entered Old English as blīths 'happiness,' later reduced to bliss."
So rather than blessing one another, let's send wishes of bliss!
