[de-kem; English des-em]
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for decem
Name said to be derived from decem, ten, referring to the fact of its being often 10-merous.
Decimate (decimo, from decem, ten, in Latin) was to take for death every tenth man of a body that had behaved very badly.An Outline of English Speech-craft
December, again, is derived from decem and imbres 'quibus abundare solet'; and so too the other numbered months.The Age of Erasmus
P. S. Allen
This book was perhaps the Dialogi decem, put into print at Cologne in 1472: Brunet.