IPA: /dɪˈteɪnər/
KK: /dɪˈteɪnər/
A person or thing that keeps someone or something in custody or possession, often related to legal situations.
The detainer was issued to hold the suspect until the trial.
Detainer → It is formed from "de-" (meaning down or away) and "tenere" (meaning to hold). The word "detainer" refers to someone who holds another in custody or keeps them from leaving.
Think of someone 'holding' ('tenere') someone 'down' or 'away' ('de-') — that's why a detainer is someone who keeps another in custody.