CONfound this infernal patriarchal system!!!
The woman gets married outdoors under the sun, and from then on she`ll have her husband's family name.
結 (bind) + 婚 (marriage)
= 結婚 (to marry)
to marry (to be married to xxx-san = ｘｘｘさん に 結婚 してる）
the marriage ceremony
結婚 (to marry) + 式 (ritual)
= 結婚式 (the marriage ceremony)