Allahu akbar in Arabic is shown below. It is translated as God is the greatest. It consists of two words, Allah and Akbar. Allah is one of the name of God and akbar is the greatest. It is from the original word kabara, meaning big or great. The muslims always chant the during war or remember Him in silence. It can be used as an appreciation of the great power of God. All in all a common phrase. It is used also to describe anything that as happened. For example, if a bad person is arrested.. You say allah akbar, he got what he deserves, god is great.
The writing of allah akbar in arabic can be made with beautiful calligraphy and hang on the walls of Muslims home.
Muslims are encourage to remember Allah by repeating the words at all time except when they are in toilet.