Jehovah Olam means The Everlasting God.
This name of God can be traced to Genesis when Abimelech and the commander of his army Phichol came to Abraham and acknowledged the presence of God in his life by saying, "God is with you" and asking him to promise to deal with him with kindness and not deal falsely with him and his offspring and his posterity.
Abraham agreed and called on the name of the Lord, Jehovah Olam, The Everlasting God. (Genesis 21:22-33)
Therefore address your prayers to Jehovah Olam when you are praying for something that you want to be established in your life, in your children's lives and for the generations that will follow long after you have died.
Click on the link to learn about other Names and Characteristics of God