1. Auxiliary verb, Ichidan verb

   auxiliary verb indicating the causative voice

   ～せる connects to -nai stem of 五段 verbs and to サ変 as さ～せる; ～させる connects to -nai stem of 一段 and カ変 verbs and to サ変 as せ～させる

2. auxiliary verb indicating the granting of permission to do something

3. auxiliary verb used as an honorific for others' actions

   Honorific or respectful (sonkeigo) languageas 〜(さ)せられる, あら〜せられる, 〜(さ)せ給う, etc.

Also written させるsaseru