noun
Refers to a person who appears on stage or at a podium to give a talk, presentation, or participate in a panel. Common in academic, conference, and formal event contexts.
学会の登壇者は、最新の研究成果を発表した。
The presenter at the academic conference presented the latest research findings.
パネルディスカッションの登壇者が意見を交わした。
The panelists in the panel discussion exchanged opinions.
講演者 refers to a lecturer or speaker giving a formal lecture. 登壇者 can be used for any stage participant, including panelists or introducers, not only lecturers.
Compound of 登壇 (toudan, 'going up on the stage') + 者 (sha, 'person'). The word is transparently derived from its components.