Sent to jail doesn’t necessarily mean sentenced, it doesn’t even mean charged or had a trial. Prison is where you go after trial, jail is where you go after an arrest. Lots of people get locked up even for long stretches without even being formally charged. Anyone placed in jail or prison is a prisoner and incarcerated. Imprisoned doesn’t necessarily mean tried or sentenced, just jailed. One can be arrested and imprisoned without ever being charged with anything. It’s actually super common in the US.