1 Happening by chance rather than intention.
1.1 Happening by a lucky chance; fortunate.
The traditional, etymological meaning of fortuitous is ‘happening by chance’: a fortuitous meeting is a chance meeting, which might turn out to be either a good thing or a bad thing. Today, however, fortuitous tends to be often used to refer only to fortunate outcomes and the word has become more or less a synonym for ‘lucky’ or ‘fortunate’ (the ball went into the goal by a fortuitous ricochet). Although this usage is now widespread, it is still regarded by some people as incorrect
Mid 17th century from Latin fortuitus, from forte ‘by chance’, from fors ‘chance, luck’.
Tentatively, without a plan, Stan proceeded across the open meadow. Fortuitous results occurred. Whether for good or ill, he’ll know in a moment.