mid-15c., "unfortunate event or circumstance," from mis- (1) "bad, wrong" + fortune. From c. 1500 as "adversity or ill fortune for which the sufferer is not directly responsible." In 19c., it was a euphemism for "illegitimate child." Related: Misfortunate.
Mischance is the lightest word for that which is really disagreeable; a mishap may be comparatively a trivial thing; both generally apply to the experience of individuals. Misfortune is the most general of these words; a misfortune is a really serious matter; it may befall a person, family, or nation. A very serious misfortune affecting large numbers is a calamity, the central idea of which is wide-spread and general mischief. [Century Dictionary, 1895]