The colors are the traditional Pan-Arab colors. The green script in the center is the Takbir ('Allahu Akbar', meaning 'God is greatest').
History
The basic tricolor dates back to 1963. The three stars were removed in 2008 to distance the flag from Saddam Hussein's Ba'ath Party. The script was originally in Hussein's handwriting but was changed to Kufic script in 2004.
Construction
A 2:3 ratio. A horizontal tricolor of red, white, and black with green Kufic script centered in the white band.