trental（n.）
"set of 30 requiem masses," 14c., also "a set of 30" generally (c. 1500); from Old French trentel (12c.) and directly from Medieval Latin trentale, from Vulgar Latin *trenta, from Latin triginta "thirty" (source also of French trente). from tri- "three" (see tri-) + -ginta "tens" (from root *dekm- "ten").
该词起源时间：14世纪