Priest's vestment (7)
(Other definitions for cassock that I've seen before include "Long clerical garment" , "Is it a habit of the clergy" , "Clerical garb" , "Chorister's robe" , "Long clerical robe" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">priest's vestment</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for alb that I've seen before include "Long white church vestment" , "White clerical garment" , "Cover" , "clerical belongings" , "Clerical gown" .)