What is the meaning of Bless?

To make something holy by religious rite, sanctify.

To invoke divine favor upon.

To honor as holy, glorify; to extol for excellence.

To esteem or account happy; to felicitate.

To make the sign of the cross upon, so as to sanctify.

To wave; to brandish.

To turn (a reference) into an object.

To secure, defend, or prevent from.

To give or send.

To approve of or assent to.

To perform the mano gesture; taking of an elder's hand to press it to one's forehead or kiss it

Used as an expression of endearment, gratitude, or (ironically) belittlement.

goodbye, bye

to bless

Source: wiktionary.org