According to "Genji monogatari Okuiri," an ancient commentary written by FUJIWARA no Teika, this title related to an anonymous ancient waka poem 'Yononakaha yumenowatarino ukihashika uchiwataritsutsu monookosoomoe' (The world is something like a floating bridge of dreams and I am lost in thought while crossing it).
藤原定家の古注釈『源氏物語奥入』では出典未詳の古歌「世の中は夢の渡りの浮橋かうちわたりつつものをこそ思へ」に関連するとしている。