What is the definition of zakat? What is the definition of al fitr?
Zakat al-fitr was declared obligatory in the second year after Hijrah. According to the scholars, who adopt the view that the word fitr comes from the same root as fitrah (creation, nature), zakat al-fitr is zakat for the body. Some people who are inspired from this view call zakat al-fitr, “head charity (charity of the bodies – zakat al-abdan)”. According to some scholars, the word fitr is related to breaking fast (iftar) and zakat al-fitr is an expression of joy, happiness, and gratitude for reaching the festival by fulfilling the duty of fasting in the month of Ramadan. This is because zakat al-fitr helps the poor to enter the festival in a better financial situation, it is an act of worship with aspects of social aid and solidarity.
Our Prophet (pbuh) stated in regards to this type of zakat that, “Zakat al-Fitr cleanses the one who is fasting from the sins of negative words he mistakenly said, and it will be food for the poor.”
 Al-Shawqani, Nayl al-Awtar, II, 406.