Duo Russian Grammar

11) Partitive

As you know, the Genitive case has lots of uses in Russian.

One of them expresses an amount of something:

  • чашка чая = a cup of tea
  • тарелка риса = a plate of rice
  • корзина яблок = a basket of apples

With mass nouns it is also used to express "some" unspecified amount of that stuff when used instead of the Accusative:

  • Я хочу воды = I want (some) water.
  • Дайте, пожалуйста, риса. = Could I have some rice, please? (literally, "Give me, please, some rice").
  • Хочешь сока? = Want some juice?

Note that this usage is only characteristic for situations when you ask or hypothesize about using "some or other amount" of a substance. You cannot actually say that you are drinking "воды" right now—but you can say that you want some (or that you sipped some in the past—with a perfective¹, of course).

чашка чаю

«Чай» has an alternative Partitive form «чаю»:

  • Хочешь чашечку чаю? = Want cup of tea?

It is optional. Actually, many short masculine nouns that denote substances used to have such form. However, «чай» is, probably, the only one where the form is immensely popular in spoken speech and does not sound old-fashioned or downright archaic.

стакан

Russian differentiates between a number of drinking vessels. Стака́н is what you call a "glass" in English: typically, a cylindrical vessel made of glass, with no handle. However, if you mean a measurement unit (quite popular in cooking), it corresponds to the English word "cup". In Russian you use not a cup or rice or flour but a "glass" of rice or flower.

  • a beer or a wine glass is «бока́л»
  • a smaller wine glass is «рю́мка»

¹ Perfective is an aspect. Russian has verbs of two flavors: those that denote "processes" and those that mean "events" (events are never used in the present). I would argue that aspect is the main culprit for consumption verbs here. You can want "воды" forever, but you aren't "drinking" it at any specific moment. Semantically, "some" water only becomes a real amount when you are done, not while you are still at it.