Pronunciation: [ɹˈe͡ɪuː] (IPA) 
The spelling of the word "raiu" can be explained with IPA phonetic transcription. In Romanian, the "r" is written as [r], which is pronounced as a trilled "r" sound. The "a" is pronounced as [a], which is an open-mid vowel sound. The "i" is pronounced as [j], which is a palatal approximant sound, and the "u" is pronounced as [u], which is a close back rounded vowel. Therefore, the spelling "raiu" in IPA phonetic transcription is [raju].
Raiu is a Romanian term that describes a meteorological phenomenon known as "black hail." It refers to a weather condition marked by the occurrence of heavy precipitation in the form of hailstones, accompanied by intense thunderstorms and darkness. This rare phenomenon is characterized by the unusual size and color of the hailstones, which can be significantly larger than regular ones, reaching diameters of several centimeters. The term "raiu" has its roots in ancient Romanian folklore, where it was believed that the black hail was caused by supernatural forces or celestial beings.
The term "raiu" is often used to depict the destructive nature of this weather event, as the heavy hailstones and thunderstorms can cause significant damage to crops, buildings, and vehicles. The darkness associated with raiu is due to the cloud cover created by the intense storm activity, resulting in a temporary dimming of daylight. This phenomenon can create a sense of eerie or foreboding atmosphere.
The occurrence of raiu is relatively rare and is most commonly observed in regions with a continental climate, such as certain areas in Romania. It is a captivating meteorological event that has been the subject of fascination and folklore for generations, inspiring stories and legends about its origins and potential supernatural influences.
