While rarely used in day-to-day conversation (well, at least rarely used in a non-expletive sense), one of the most frequently used words in our Bible is “lord.” Simply defined by Miriam-Webster, a lord is “one having power and authority over others.” Throughout the Bible, both humans and God are referred to as “lord,” but there is a fundamental difference between the relative lordship of a human and the absolute Lordship of God. Recognizing this, a tradition has developed within English Bible translations to acknowledge that fundamental difference and to help the reader understand who is being referred to.
Whenever a human is being referred to, the word is kept lowercase: lord. So, in Acts 25:26, Festus is recorded as saying, “But I have nothing definite to write to my lord about him,” referring to the Roman emperor, Nero. However, when God is being referenced, English translators indicate this by capitalizing the first letter regardless of where the word is in a sentence: Lord. This capitalization is used of any member of the Trinity, and is often used of Jesus. So, at the beginning of Paul’s letters we frequently read something along the lines of, “Grace to you and peace from God our Father and the Lord Jesus Christ.”
Finally, there is a special usage of the word lord in our English Bibles: Lord. This style of the word, with all uppercase letters, is a special identifier used in many translations to alert the reader that the divine name is being used. This special usage is only going to be found in the Old Testament (see, for example, Exodus 34:5–6). The divine name is approximated by the English letters Y-H-W-H, but the precise pronunciation is not known with certainty. (Note: “Jehovah” is an attempt at pronouncing YHWH, but is almost certainly incorrect; “Yahweh” is likely the closest thing to a correct pronunciation). Well before the time of Jesus, the Jewish people, out of respect for God’s name, stopped speaking the name out loud. So, when reading the text of Scripture, instead of vocalizing “YHWH,” they would instead say out loud “Lord” or “The Name.” While there is no biblical instruction to not utter God’s name, the tradition of saying “Lord” in place of “YHWH” seems to be implicitly approved of by the New Testament which refers to God as “Lord,” but not “YHWH.” While there are some English Bibles that spell out YHWH, most translations follow the custom begun by the Jews and followed by the apostles, translating the divine name as “Lord”.
I hope this information is useful for your Bible studies!
Studies in the Bible 