Theta topic's main category Category:Theta (letter)
Theta (UK: , US: ; uppercase: Θ or ϴ; lowercase: θ or ϑ; Ancient Greek: θέτα thē̂ta [tʰɛ̂ːta]; Modern: θήτα thī́ta [ˈθita]) is the eighth letter of the Greek alphabet, derived from the Phoenician letter Teth . In the system of Greek numerals, it has a value of 9.