vinculum

Vinculum, vinculi, n., second declension, from vincio, vincire, vinxi, vinctum, "to bind". Poets often write the syncopated vinclum, which scans better, and manuscripts of any period may give either.

The plural does most of the work: vincula are chains, and by extension imprisonment, so "in vincula dare" is to throw into gaol and "in vinculis esse" to be inside. The corpus spells the forms uincula and uinculis, u for v being ordinary scribal practice, not a different word. Ecclesiastical Latin keeps the figurative sense alive in "vinculum matrimonii", the marriage bond that canon law spends centuries arguing about. The trap is the near-identical vinco, vincere, "conquer": different root, different verb, and a text about vincula is about prisoners, not victories.