-end Also -endum.
[Latin -endus, -enda, -endum, endings of gerunds.]
This ending has never been active in the language, and the only examples are those that have been drawn directly from Latin gerunds, verb forms that function as adjectives with the sense of something that should or must be done.
Apart from dividend and reverend, examples are specialist or archaic; in mathematics, the subtrahend is a quantity or number to be subtracted from another, the minuend; a prebend (Latin praebere, to grant), now only historical, was the portion of the revenues of a cathedral or collegiate church granted to a canon or member of the chapter as salary or expenses.
The neuter gerund ending -endum is preserved in a number of Latin words brought over into English: addendum (literally ‘that which is to be added’) is an item appended to the end of a book or other publication; corrigendum (Latin, from corrigere, bring into order) is something to be corrected, typically an error in a printed book; referendum (Latin referre, carry back) is a general vote by the electorate on a political question. For their plurals, see -a2.