A more thorough explanation:

Retenementum

Retenementum is an old word that means to hold back or keep something or someone from moving or leaving. It is a type of restraint or detainment.

• The king ordered the retenementum of the prisoner until his trial.
• The teacher used retenementum to keep the students in the classroom during a lockdown.

These examples show how retenementum was used in the past to keep someone or something from moving or leaving. The first example shows how a prisoner was held back until his trial. The second example shows how a teacher used retenementum to keep students safe during a lockdown.