fortuitous
for-TOO-ih-tusadjMeaning happening by chance, often by lucky chance
Memory hook FORTUNE by CHANCE. Caught in the rain, Lila ducks under a shop awning and finds her old best friend sheltering there too; the meeting, pure chance and good fortune, is fortuitous.
Our meeting at the airport was fortuitous: neither of us knew the other was flying that day.
In context The discovery was fortuitous rather than planned; the scientist had been studying something else entirely when she noticed the strange glow in her dish.
Similar chance, accidental, unplanned, lucky
Opposite planned, intended, deliberate
From Latin fortuitus, “happening by chance,” from fors (chance).