Passover defined (March 30 - April 7) -- for year of 2018 (Western Calendar reckoning)

from CHABAD dot-org:

• Passover 2018 will be celebrated from March 30- April 7.
• The first Seder will be on March 30 after nightfall, and the second Seder will be on March 31 after nightfall.
• Passover is celebrated by eating matzah (unleaven bread) and maror (bitter herbs).
• For the duration of the 8 (or 7 days in Israel) of Passover, chametz (leaven) is strictly avoided.

What Is Passover?

The eight-day festival of Passover is celebrated in the early spring, from the 15th through the 22nd of the Hebrew month of Nissan, March 30-April 7, 2018. Passover (Pesach) commemorates the emancipation of the Israelites from slavery in ancient Egypt. Pesach is observed by avoiding leaven, and highlighted by the Seder meals that include four cups of wine, eating matzah and bitter herbs, and retelling the story of the Exodus. 

In Hebrew it is known as Pesach (which means “to pass over”), because G‑d passed over the Jewish homes when killing the Egyptian firstborn on the very first Passover eve.

https://www.chabad.org/holidays/passover/pesach_cdo/aid/871715/jewish/Passover-Pesach-2018.htm