Zakat is one of the Five Pillars of Islam, serving as a mandatory act of charity. Its importance and practice are deeply rooted in Islamic faith and socio-economic welfare. Here's a detailed overview:

1. Meaning and Purpose: The term "zakat" literally translates to "purification" and "growth" in Arabic. It represents a form of alms-giving and religious tax in Islam. By giving zakat, Muslims purify their wealth and souls, and it helps in redistributing wealth in society, thereby reducing economic disparity.

2. Eligibility and Calculation: Zakat is obligatory for adult Muslims who meet the necessary criteria of wealth, known as the "nisab." The nisab is the minimum amount of wealth a Muslim must possess before they are liable to pay zakat. This threshold varies depending on the current value of gold or silver. Zakat is typically 2.5% of a Muslim's total savings and wealth, calculated over a lunar year.

3. Beneficiaries: There are specific categories of people who are eligible to receive zakat, as mentioned in the Quran. These include the poor, the needy, those employed to collect zakat, to reconcile hearts, free captives, help those in debt, for the cause of Allah, and for the stranded traveler.

4. Significance in Society: Zakat plays a crucial role in Islamic societies. It's a key tool for social welfare and poverty alleviation. By redistributing wealth from the richer segments of society to the poorer, zakat helps in balancing social inequality and is seen as a form of social solidarity.

5. Zakat al-Fitr: Apart from the zakat on wealth, there's a special form of zakat called "zakat al-Fitr" which is paid at the end of Ramadan, before the Eid al-Fitr prayers. This is a smaller form of zakat that is obligatory for all Muslims, regardless of their age or financial status, and is aimed to purify those who fast from any indecent act or speech and to help the poor and needy.

6. Modern Application: In the contemporary world, the practice of zakat has adapted to include modern financial systems. Muslims around the world pay zakat through various means, including online payments, to organizations that distribute the funds to those in need.

Zakat is not just a religious obligation but also a tool for social justice and economic redistribution in Islamic societies, reflecting the deep commitment of Islam towards caring for its community members.