auxiliary verb / ichidan verb:

• auxiliary verb indicating the causative - せる is for 五段 verbs, させる for 一段; follows the imperfective form of (v5) and (vs) verbs; senses 1-3 of せる are sometimes abbreviated as 〜す
• auxiliary verb indicating that one has been granted the permission to do something - usu. as 〜(さ)せてもらう, 〜(さ)せていただく, etc. - humble language
• auxiliary verb used as an honorific for others' actions - as 〜(さ)せられる, 〜あら(さ)せられる, 〜(さ)せ給う, etc. - honorific language