presa
noun
pre·sa ˈprā-sə 
: a symbol in music notation usually resembling an S that indicates the point of entry of the successive voice parts of a canon
called also guida
Word History
Etymology
Italian, literally, action of taking, seizure, from feminine of preso (past participle of prendere to take, seize), from Latin prehensus, past participle of prehendere to take, grasp, seize