Let's break it down:
* Es: This is the verb "to be" in the third person singular present tense, meaning "it is".
* el: This is the definite article "the" in Spanish.
* diecisiete: This means "seventeen".
* de: This is the preposition "of", indicating a relationship to the following word.
* abril: This is the month of April in Spanish.
Therefore, the entire phrase translates to "It is the seventeenth of April".