probabilidad
probability
probable
likely to happen
+
-idad
noun suffix (similar to -ity)
Probabilidad means probability and can be thought of as probable0 + -idad1, where -idad1 turns the adjective into a noun, just like '-ity' in English.
noun
- probabilityThe likelihood or chance of something happeningHay una alta probabilidad de lluvia mañana. // There is a high probability of rain tomorrow.