It's a very good question because if you are a Christian you probably use the term all the time and have a general idea of what it is, but if someone asked, you would probably have a hard time explaining it. The following is an in-depth look at what God’s Glory really means.

Part of the confusion comes from the fact that Glory can be used in more than one way. In the simplest of terms, God's glory is the essence of His nature, and we give glory to Him by recognizing that essence.

https://www.gotquestions.org/glorify-God.html

WHAT IS THE SIGNIFICANCE OF THE GLORY OF GOD?

Glory vs. Glorified. There is no truth in the Bible more fundamentally pervasive than God's zeal to be glorified, which is that he desires for us to think, feel, and act in such a way as to make him as beautiful as he is. The glory of God is the public recognition of his inestimable value.

Holiness is defined as the intrinsic value of God, the value of his being. And when that goes public, humanity is manifesting God's glory, because we are created in his image, and we trust his promises so that we make him look magnificently trustworthy. 

Therefore, God's glory is the radiance of his holiness, the radiance of his many, infinitely worthy, and valuable perfections. Read more in this article in desiringGod.org as written by John Piper.

THE GLORY OF GOD IS THE BEAUTY OF HIS SPIRIT

There is no aesthetic beauty or material beauty in his character, but rather, it is the beauty he carries in him, at the base of all that he really is.

According to Isaiah 43:7, God created us for his glory. In context with the other verses, it can be said that man “glorifies” God because through man, God’s glory can be seen in things such as love, music, heroism and so forth—things belonging to God that we are carrying “in jars of clay” (2 Corinthians 4:7). We are the vessels that "contain" his glory.

Everything we are capable of doing and being comes from Him. As stated in Psalm 19:1-4, “The heavens are telling of the glory of God and their expanse is declaring the work of his hands; day to day pours forth speech, and night to night reveals knowledge. There is no speech, nor are there words; their voice is not heard. Their line has gone out through all the earth, and their utterances to the end of the world.”

Psalm 73:24 calls heaven itself “glory.” It was common for Christians to speak of death as being “received unto glory”. When the Christian dies, he will be taken into God’s presence, and in his presence will be naturally surrounded by God’s glory. Again, the beauty of his Spirit (or the essence of Who He Is) is his “glory.” In that place, his glory will be seen clearly, just as 1 Corinthians 13:12 says, “For now we see in a mirror dimly, but then face to face; now I know in part, but then I shall know fully just as I also have been fully known.”

https://www.gotquestions.org/glory-of-God.html

EPIPHANY

Then the LORD’s glory rose from above the winged creatures and moved toward the temple’s threshold. The temple was filled with clouds, and the courtyard was filled with the brightness of the LORD’s glory.

Ezekiel 10:4 gives us a glimpse of God’s glory through the above passage. The word translated here as “glory” is kabod in Hebrew. Interestingly, this word is rooted from the basic meaning of “heavy” as well as a word meaning “rich.” Speakers of ancient Hebrew would refer to a rich person as “heavy in wealth”. A similar extension of the literal sense of kabod included being loaded with power, reputation, or honor. From the use of this word, we can understand the meaning of glory. Glory means God's weightiness in virtues like might, beauty, goodness, justice, and honor. As for these characteristics and so many others, God has them in abundance.

As a result, when we think of God’s glory, we remember that God has all good things in greater quantity and quality than we can ever imagine. Moreover, God is the source of all good things. He actually shares his glory with us. When we receive his plentiful gifts with gratitude, when we use them to enhance his honor, when we acknowledge Him as the source of all goodness, then we are glorifying him.

Find out more about the glory of God by reading the insights provided by theologyof work.org. 

WHAT DOES THE GLORY OF GOD TEACH US?

“Arise, shine, for your light has come, and the glory of the Lord has risen upon you. For behold, darkness shall cover the earth, and thick darkness the peoples; but the Lord will arise upon you, and his glory will be seen upon you” (vv. 1–2). - Isaiah 60:1–3

Our minds are often flooded with images of brilliant light when we think of the glory of the Lord. It is certainly fitting, as Scripture often describes the glory of God in terms of a light that shines brighter than anything that we experience on earth. For example, the above passage speaks of the glory of our Creator and not the sun being the light that shines forth in this dark world, revealing itself through God’s people that they might point the pagan nations unto the Lord of all. Revelation 21:22–25 teaches us that in the new heaven and earth, creation will have no need for the sun by day or the moon by night because the glory of the Lord shall illuminate all of creation.

Other biblical passages connect God’s glory with his holiness and weightiness, that is, His significance. It is particularly evident in Leviticus 10:1–3 and the account of Nadab and Abihu, who offered strange fire before the Lord. The meaning of "strange fire" is not clearly defined by Moses, but it is clear enough that Nadab and Abihu acted without regard for consequences. As a result, they did not reverence God in a proper manner and were unaware of His dignity as God. Consequently, they were consumed by fire from atop because they did not glorify the Lord.

These are interesting views as pointed out in ligonier.org. Read the entire article here.

THE GLORY OF GOD IN THE TIME OF JESUS

According to compellingtruth.org, Jesus shares the glory of God in the New Testament, telling us, "This illness does not lead to death. It is for the glory of God, so that the Son of God may be glorified through it" (John 11:4; also verse 40). Jesus spoke of resurrecting Lazarus from death in this context. The act would bring glory to God and honor Jesus. While in Acts 7:55, Stephen looked into heaven just before his death and saw the glory of God. In this context, it referred to the greatness of God in heaven.

In Romans, the term "glory of God" is used three times. Romans 3:23 mentions all have sinned and fall short of the glory of God. Romans 5:2 declares the glory of God in the sense of His greatness. Romans 15:7 shares, "Therefore welcome one another as Christ has welcomed you, for the glory of God." Here, glory is used in the sense of honoring God,

Hebrews 1:3 uses the same concept in another way, stating, "He is the radiance of the glory of God and the exact imprint of his nature, and he upholds the universe by the word of his power." This presents Jesus as the radiance of God's glory. Revelation expresses God's glory in three clear passages. First, Revelation 15:8 speaks of the sanctuary being filled with the glory of God. Revelation 21:11 notes the glory of God coming from the New Jerusalem. Revelation 21:23 adds that the glory of God serves as the light for the city.

In summary, the glory of God is used in a multitude of ways. It can refer to God's greatness, His honor, His beauty, His power, and His light. Whenever we appreciate the glory of God, we are acknowledging the strength of the Lord and the worthiness of his name to be honored and praised.