Koolen is a Dutch patronymic surname, deriving from the given name Nicolaas, the Dutch form of Nicholas. Patronymic surnames like Koolen are formed by adding a suffix indicating "son of" to a personal name. In this case, the suffix "-en" is a common Dutch variant meaning "son of" (related to "-sen"). Thus, Koolen originally meant "son of Kool" or "son of Nicolaas", where "Kool" itself is a short form of Nicolaas. This type of suffix is typical in Dutch surnames, particularly in northern provinces. The name Philip Benedictus Nicolaas ultimately derives from the Greek name Nikolaos, meaning "victory of the people" – from nike (victory) and laos (people). The name spread widely due to the fame of Saint Nicholas, a 4th-century bishop of Myra (in modern-day Turkey). He is the patron saint of children, sailors, and merchants, and the inspiration for Santa Claus (via Dutch Sinterklaas). The name Nicholas has been common in Christian countries; in England it became popular after the Norman Conquest and remained frequent through the Middle Ages, despite a decline following the Protestant Reformation. It has been borne by five popes and two tsars of Russia. Geographical distribution Koolen is a relatively rare surname, concentrated in the Netherlands. According to surname distribution maps, it is most frequent in the southern provinces, possibly pointing to a origin in the Catholic regions where the name Koolen is common. While not among the most common Dutch surnames, it is well-known in the Netherlands. The surname has other languages/cultures: Russian Nikolaev, Nikolaeva; Macedonian Nikolov, Nikolova; Serbian Nikolić; and Slovak Mikula. Related cases Note that the article from Wikipedia titled "Koolen (lake)" describes a lake in Russia; the name of the lake originates from Chukchi word Koolёn meaning "fault" or "deep chasm". This is coincidental and not connected to the Dutch surname. Meaning: "son of Kool" (short form of Nicolaas)Origin: DutchPattern: Patronymic suffix -enUsage regions: Particularly Netherlands