1.
99th birthday; celebration of one's ninety-ninth year
A traditional celebration of a person's 99th birthday. The name plays on the fact that removing the top stroke from 百 (hundred) leaves 白 (white), i.e., "hundred minus one."
白寿のお祝い。
A 99th-birthday celebration.
白寿 celebrates a person's 99th birthday, the last of the widely celebrated Japanese longevity milestones (長寿のお祝い). The name plays on 百 (hundred): removing the top stroke of the character leaves 白, giving "hundred minus one"; the traditional celebratory color is white.
Common collocations
Types
Part of a sequence of longevity milestones: 古希 (70), 喜寿 (77), 傘寿 (80), 米寿 (88), 卒寿 (90), 白寿 (99).