Beta (UK // or US //; uppercase Β, lowercase β, or cursive ϐ; Ancient Greek: βήτα bḗta or Modern Greek: βήτα víta) is the second letter of the Greek alphabet. In Ancient Greek, beta represented the voiced bilabial plosive /b/. In Modern Greek, it represents the voiced labiodental fricative /v/. Letters that arose from beta include the Roman letter 〈B〉 and the Cyrillic letters 〈Б〉 and 〈В〉.
Like the names of most other Greek letters, the name of beta was adopted from the acrophonic name of the corresponding letter in Phoenician, which was the common Semitic word *bayt ('house'). In Greek, the name was βῆτα bêta, pronounced [bɛ̂ːta] in Ancient Greek. It is spelled βήτα in the modern monotonic orthography, and pronounced [ˈvita]. In US English, the name is pronounced /ˈbeɪtə/, while in British English it is pronounced /ˈbiːtə/.