Kubyshka

Kubyshka is an early East Slavic ceramic jar or pot with narrow hole, short or absent neck and wide, rounded body. In the past the term "kubyshka", a diminutive derivation from the word "Куб" ("kub") in the generic meaning of "container", had a broader meaning of various rounded containers, e.g. a barrel or birch bark kubyshka.
The word has become associated with buried hoards and is used in a number of idioms associated with hoarding or reserve saving (держать в кубышке (keep in a kubyshka), класть в кубышку (put into a kubyshka), etc.).
The word is also used as a euphemism or a nickname for a short, plump person. For example, in Sergei Prokofiev's ballet "Cinderella", a wicked stepsister's nickname Kubyshka was variously translated as Fatty, Dumpy, etc. Princess Anastasia, the daughter of tsar Nicholas II of Russia was nicknamed "Kubyshka". "