leader; person in charge of a group
Refers to someone who leads or supervises a group, such as on a school trip, tour, or organized activity. Often implies responsibility for the group's conduct and safety.
The leaders on the school trip are the teachers.
Please act according to the leader's instructions.
案内人 is a guide who shows the way or provides information, whereas 引率者 is more about leading and taking responsibility for a group.
Compound of 引率 (leading, commanding) and 者 (person). 引率 itself is from 引く (to pull, to lead) and 率いる (to lead, to command).