Zakat - This is the giving of 2.5% percentage of your wealth in cash or a useable form to specified classes of people. It is required once a year.
ZAkat-ul-Fitr - An obligatory Sadaqa to be given by Muslims before the prayer of Id-al-Fitr.
Zamzam - The sacred well inside Al-Haram ash-Shareef in Mecca.
Zanadiqah - Atheists
Zarnab - A good smelling grass.
Zuhr - Noon, mid-day Salaat.