Lord
(in small letters or initial capital) is used in this Bible to mean "master" or someone who is in control. Sometimes this can be a title of respect for a human being.
It is usually used for God as a title showing his power over all things.
The early followers of Jesus said "Jesus is Lord" to mean that he has authority over everything.
LORD
(in all capital letters) is used in this Bible to refer to the personal name of God. The Hebrew word for this name is Yahweh, which means "I AM WHO I AM." This name tells us that God is always with his people.