Definition of trentals:
(n) :
(Christianity) A set of 30 requiem masses, said once a day for a month or all in one day.
(n) :
(Christianity) The payment for this service.
(n) :
(Christianity, archaic) Synonym of month's mind, the commemorative service held on the 30th day after burial.
(n) :
(figurative, obsolete) Synonym of elegy, any funeral or funereal song or poem.
(n) :
(figurative, rare, obsolete) Synonym of triacontad, any set of thirty things.