It is the feminine singular form of the noun "sorpresa" (surprise), which is a noun of feminine gender in Spanish.
Here are some examples of how "la sorpresa" can be used in a sentence:
* ¡Qué sorpresa! (What a surprise!)
* Me encanta dar sorpresas. (I love giving surprises.)
* La sorpresa de su cumpleaños fue un éxito. (The surprise for his birthday was a success.)