The word Zakah comes from the Arabic root z-k-w, which literally means purification or growth. In its linguistic sense, Zakah refers to the act of purifying or cleansing. When applied as an Islamic obligation, it denotes the purification of one's wealth by setting aside a prescribed portion for those in need.
While Zakah functions as a form of charitable giving, the question specifically asks for its literal meaning, not its practical function. The distinction matters: charity (sadaqah) is a broader voluntary concept, whereas Zakah is an obligatory act of worship whose very name signals that paying it purifies the remainder of a Muslim's wealth and soul. The terms donation and tax describe aspects of how Zakah operates but do not capture the root meaning of the Arabic word itself.
In examinations, pay close attention to whether the question asks for a literal meaning, a technical definition, or a practical description, as these can point to different answers.