A
washing cup in Judaism is the special vessel used to wash the hands and purify them in the morning and prior to eating a meal (with bread) as well as before entering a holy place like the Western Wall. This ritual washing of the hands is referenced in the Mishnah and the Talmud (Gemarah) and is observed mainly by orthodox Jews, and conservative Jews with some exceptions. Not every hand washing ritual or custom is the same, as in the morning wash, the hands are rinsed from the water in the cup on alternating sides six times, whereas before breaking bread, the hands are

generally washed thrice on one hand and then thrice on the other hand. Both times, the right hand comes first. Both times, the washing is followed by the blessing over washing the hands: Blessed are you, Lord our God, King of the universe, who has sanctified us with His commandments, and has commanded us on the washing of the hands.
בָּרוּךְ אַתָּה יְהוָה אֱלֹהֵינוּ מֶלֶךְ הָעוֹלָם, אֲשֶׁר קִדְּשָׁנוּ בְּמִצְווֹתָיו, וְצִוָּנוּ עַל נְטִילַת יָדָיִם
Baruch Ata A-donai, Elo-heinu Melech HaOlam, asher kideshanu bemitzvotav vetzivanu al netilat yadayim.
Traditionally, this ritual washing, oft referred to as '
Netilat Yadayim', is done with a special item of Judaica, a unique washing cup with two handles, to grasp and switch hands while spilling the water inside on the hands, a little at a time. Any vessel can be used, as long as it is big enough to hold the right amount of water for washing both hands, but most Jewish homes have specialized cups for the purpose. These cups may beautiful, decorative, or simple. They can be made of ceramic, metal, plastic, or other materials.
The Gemarah speaks of a second washing that is done after the meal, and this is called Mayim Acharonim (last waters). It fell by the wayside in comparison to the important washing of the hands before the meal but has recently been revived and the tradition is a lovely one, a health measure of hygiene after a meal. People who practice this custom often do it on special occasions and Shabbat, and it can be done with a smaller cup. People may have a special small Judaica set for mayim acharonim that comes with a small decorative basin and cup to wash the fingertips with at the table, rather than getting up to wash in a sink.