It is the ritual that turns an ordinary meal into the opening of sacred time.
Kiddush sanctifies the day
Britannica defines Kiddush as the benediction recited over a cup of wine before the meal on the eve of the Sabbath or a festival, acknowledging the sanctity of the day. My Jewish Learning makes the same point in more direct language: Kiddush is the blessing over wine or grape juice that sanctifies Shabbat and holidays.
That is the key word: sanctifies.
The ritual usually happens in the home
Britannica notes that the chant is usually performed by the head of household and that everyone present then sips from the cup.
This matters because Kiddush is one of the clearest ways Jewish ritual anchors holiness in domestic life rather than only in synagogue.
Kiddush sets the meal inside sacred time
The ritual comes before eating because the meal is no longer just dinner. Time has changed, and the meal acknowledges that change.
Why it still matters
Kiddush still matters because it teaches that holiness should be named before it is consumed. Jewish time becomes real through repeatable acts, not sentiment alone.
The shortest accurate answer
Kiddush is the Jewish blessing over wine recited at the start of Shabbat or a festival meal to acknowledge and sanctify the day.