συγκυρία & παρατυγχάνω
συγκυρία - from συν(prep.) ‘with, together’ + κυρέω ‘happen, come to pass’
παρατυγχάνω - from παρα(prep.) ‘beside, present’ + τυγχάνω ‘meet, hit upon’
These are synonyms in Greek, though etymologically unrelated. Both are hapax legomena (occurring but once in the NT), and both authored by Luke in Luke 10.31 and Acts 17.17 respectively.
Like other pagan peoples, the Greeks and Romans deified Luck or Chance. For the Romans this was Fortuna, and for the Greeks the goddess Τύχη, the noun derived from the verb τυγχάνω.
Nevertheless, both συγκυρία and παρατυγχάνω carry the sense of an unexpected or unforeseen coincidence, without any reference to Luck, per se. This can be pictured by a scene where I am walking down a street, and you are walking down the cross street, each of us unbeknownst to the other. Then we “happen to meet” at the intersection, “by chance” as some might say.
In the parable of the Good Samaritan many translations have something akin to “by chance a certain priest…” These translations could be improved by removing any potential reading which lends credence to the personification of Luck, a thing clearly not in the mind of Luke the author. This is the man who wrote concerning the confluence of portentous events that “the Gentiles and the people of Israel, were gathered together to do whatever Your hand and Your purpose determined before to be done.” A better translation might be “a certain priest happened to come down the road” or “By happenstance a certain priest came down the road”
The translations of Acts 17.17 are generally more in accord with this, along the lines of “he reasoned in the synagogue … with those who happened to be there”
Examples: Luke 10.31, Acts 17.17