also: ばんいち · まんいつ · ばんいつ
noun
emergency; worst-case scenario; unlikely event
Refers to a highly unlikely but serious situation; often used in conditional or hypothetical contexts. The literal gloss '10000 to 1' is a figurative expression of extreme unlikelihood.
万一のことがあったら、この番号に電話してください。
If something should happen (in the unlikely event of an emergency), please call this number.
万
I have insurance just in case (to prepare for the worst).
adverb, noun which may take the genitive case particle 'no'
if by any chance; in the unlikely event that
Adverbial use expressing a remote possibility; often paired with conditional forms like ～たら, ～ば, or ～ても.
万一雨が降ったら、試合は中止です。
If by any chance it rains, the game will be canceled.
万一のことがあっても、慌てないでください。
Even in the unlikely event that something happens, please don't panic.