It means "of" or "from".
The indefinite article "de" in Spanish is analogous to the indefinite article "of" in English.
de means of in spanish
Trienta de octubre translates from Spanish to mean the 30th of October.
De.
de que: from what
De = from. Para = to.
El = The De = Of
IT doesn't mean anything in Spanish. Perhaps you meant:"de mañana", an expression used in Spanish to mean "in the morning"
Of.
of the
Of where/from where
de missio = of missio