A Kiddush cup is a Jewish ritual object often presented as a bar mitzvah gift for holding wine.
Kiddush is the blessing that sanctifies Shabbat and Jewish festivals, and the blessing is traditionally recited over wine or grape juice. The cup used for this purpose is called a kos Kiddush, commonly translated as Kiddush cup.
Decorative Kiddush cups are popular gifts because they connect the celebrant with future participation in Jewish ritual. A cup may be made from silver, glass, ceramic, or another material, and designs vary widely across communities.
A Kiddush cup is not the same as a mezuzah, shofar, or set of tefillin. Those objects have different ritual purposes. Also, receiving a cup at a bar mitzvah does not by itself create a religious obligation; it is a meaningful customary gift.