For*tu"i*tous (?), a. [L. fortuitus; akin to forte, adv., by chance, prop. abl. of fors, fortis, chance. See Fortune.] 1. Happening by chance; coming or occuring unexpectedly, or without any known cause; chance; as, the fortuitous concourse of atoms.

It was from causes seemingly fortuitous . . . that all the mighty effects of the Reformation flowed.

So as to throw a glancing and fortuitous light upon the whole.

2. (LAw) Happening independently of human will or means of foresight; resulting from unavoidable physical causes. Abbott.

Syn. -- Accidental; casual; contingent; incidental. See Accidental.

-- For*tu"i*tous*ly, adv. -- For*tu"i*tous*ness, n.

• happening by chance, not necessarily a lucky chance
  
• Describing a coincidence or accident, usually meant as one that is fortunate.