Declensions

In Latin there are five declensions.

Nouns in Latin have five declensions.

Swedish nouns are generally divided into five declensions.

Studying a table of Russian paradigms, Mary unconsciously knitted her brows and scratched her head. She marvelled that most Russian six-year-olds master the noun declensions with little apparent effort.

I believe there's an old Soviet joke about a CIA agent who gives himself away by correctly using declensions of Russian numbers.