What does it mean that woman is the glory of man?
"For a man indeed ought not to cover his head, since he is the image and glory of God; but woman is the glory of man. For man is not from woman, but woman from man. Nor was man created for the woman, but woman for the man" (I Corinthians 11:7-9).
This is a reference back to the Creation. God made man directly: "And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living being" (Genesis 2:7). Therefore man is made in the image of God and his existence brings honor (or glory) to God. Woman was also made in the image of God. "So God created man in His own image; in the image of God He created him; male and female He created them" (Genesis 1:27). However, woman was created from man who already existed. "And the LORD God caused a deep sleep to fall on Adam, and he slept; and He took one of his ribs, and closed up the flesh in its place. Then the rib which the LORD God had taken from man He made into a woman, and He brought her to the man" (Genesis 1:21-22). Her existence brings honor to the one she came from, man.
Paul also argues that women bring honor to men because women were made by God for men. "And the LORD God said, "It is not good that man should be alone; I will make him a helper comparable to him"" (Genesis 2:18). Because woman was made to be a companion for man, she brings honor to man by being there.
Think of it in this manner: You make a birthday cake for your father, decorating it very beautifully. That cake gives you honor because people look at it and say, "You made that! It's gorgeous!" That cake also gives your father honor because it was made for him. "What a special cake! Your daughter must really love you!" So even though the cake doesn't do anything in particular, it brings honor to its origins and to the one it was given.