Mike Ratliff writes:
In the English translations of the Old Testament when we encounter the word “Lord” we are actually reading the Hebrew word “Adhōnāy.” On the other hand, when we read the word “LORD,” it is is completely different Hebrew word, “Yehōwāh.” “Adhōnāy” is actually a title for God meaning “sovereign one.” “Yehōwāh” is the sacred name of God. It was the name He used to reveal Himself to Moses at the burning bush. “Yehōwāh” is the unspeakable name, the holy name of God. The Hebrew scribes wrote it as “YHWH.” Therefore, it is referred to as the sacred tetragrammaton, the unspeakable four letters. “Adhōnāy” is the plural noun form of “Ādhōn,” which, when used in reference to God, means Lord. However, “Adhōnāy” is plural but singular in meaning. This speaks of the Holy Trinity, i.e. One God in three persons.