Most of us "sorta" know what the Latin phrase means, but sometimes it helps to get phrases like that nailed down. D. A. Carson does that in the preface to his book, The God Who Is There. He writes:
For years I have usually placed after my name, in the prefaces of the books I have written, the Latin phrase Soli Deo gloria, and I am about to use it again. The phrase means "Glory in God alone" or "to God alone be glory." It was one of five phrases developed about five hundred years ago to summarize a great deal of Christian truth--in this case the truth that everything that is done should be done for God's praise, to the exclusion of human self-glorification and pomposity. The great composer Johann Sebastian Bach appended the initials of the phrase "SDG," to the musical manuscripts of each of his cantatas; it was similarly used by his contemporary George Frideric Handel (best known for what we commonly call "Handel's Messiah"). It is a small acknowledgment of something found in the very Bible that we are about to read, in 1 Corinthians 10:31: "So whether you eat or drink or whatever you do, do it all for the glory of God."