The term "muktzah." Shabbat vs. yom tov - when it comes to items with a permissible purpose on yom tov that is prohibited on Shabbat. But shouldn't all details of Shabbat and yom tov be the same outside of food prep? And yet, that's not necessarily the case. Also: the shards of broken vessels can be treated like the vessels themselves would have been, as long as they serve a purpose.... more of less specifically. Depending on when the vessel broke, in terms of determining its Shabbat use. Note: Designating a purpose to every given vessel for use on Shabbat must take place before Shabbat. And again, the question of the permitted melakhot on yom tov that are more limited because of the details of Shabbat.