What do we call the medieval Christian practice of admitting sins to a priest?

The story behind the answer

This term refers specifically to telling one’s sins aloud to a priest, who then offers guidance, assigns a penance, and—if the sinner is contrite—pronounces absolution. By contrast, absolution is the priest’s act of forgiveness, penance is the remedial act assigned (like prayers or fasting), and repentance is the inner sorrow and resolve to amend one’s life.

In the Middle Ages, the practice shifted from earlier public admissions of sin to private, “auricular” sessions influenced by Irish monastic custom. The Fourth Lateran Council (1215) made annual disclosure of grave sins to one’s parish priest obligatory, tying spiritual health to regular moral accounting. Clergy used penitential handbooks to guide questions and remedies, and the inviolable “seal” meant priests could never reveal what they heard, reinforcing trust in the sacrament.