The pluralization of adon "my lord" is adonai "my lords." Otto Eissfeldt theorizes that adonai is a post positive element attested to in Ugaritic writing. He points to the myth of the struggle between Baal and Yam as evidence.: 531 Some theorize that adonai was originally an epithet of the god Yahweh depicted as the chief antagonist of "the Baʿals" in the Tanakh. Only later did the epithet come to be used as a euphemism to avoid invoking the deity's proper name, Yahweh.
In Canaanite/Ugaritic tradition, ʾadn ilm, literally "lord of gods" is an epithet of El.: 532 However, ʾadn "lord" could also be an epithet of other gods. When Yam is described as being at the zenith of his might, he is proclaimed ʾadn or "lord" of the gods.: 532 In some Ugaritic texts the term ʾadn ʾilm rbm meaning "the Lord of the Great Gods" is used to refer to the lord and father over deceased kings.: 532  Some think that this is a reference to Baal. Other suggest this is a reference to a human necromancer, who was traveling to the land of the dead. Karel van der Toorn disagrees; he believes that it is a reference to Milku, Yaqar or Yarikh, or possibly El.: 532 Ugarit family households were modeled after the structure of the divine world, each headed by an ʾadn meaning in this context "master" or "patron". Generally, this was the patriarch of the family and there may be some relation between ʾadn and the Ugarit word for "father", ʾad.
The name of the Greek god Adonis is similar to a Semitic word—adon (which means "lord"). Yet there is no trace of a Semitic deity directly connected with Adonis, though there most likely was. There is also no trace in Semitic languages of any specific mythemes connected with his Greek myth. Both Greek and Near Eastern scholars have questioned the connection.
In the Hebrew Bible, adoni means "my lord", and is a term of respect that may refer to God or to a human superior, or occasionally an angel, whereas adonai (literally "my lords") is reserved for God alone. In Jewish tradition, the pluralization can be used to distinguish God from earthly lords and to increase his majesty. However, many modern critical scholars see the use of a plural as a remnant of a polytheistic past, with the word only later coming to refer to Yahweh, the single god of Judaism. It is thought that at least some biblical authors used the word originally in a polytheist sense.: 531