Definitions for "Father of the Bride"
He usually is to pay for the wedding and escorts the bride down the aisle.
In traditional wedding circles, this guy fronts most of the cash -- that's no small feat. In addition, brides' dads have picked up additional to-dos along the way. Dad's chores might include airport duty, coordinating maps/directions to the wedding site, scouting potential locations, doling out tips to wedding day staff, and a variety of toasting and hosting tasks.
He used to pay for everything at a wedding but nowadays both families often share the costs. What has not changed is his duty of escorting his daughter down the aisle in her last few moments of being single.