Theta

Theta (, ; uppercase Θ or '; lowercase θ' or ''; }} thē̂ta ; Modern: |}} thī́ta ) 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.''
In Ancient Greek, θ represented the aspirated voiceless dental plosive , but in Modern Greek it represents the voiceless dental fricative .
In its archaic form, θ was written as a cross within a circle... meer