The article analyzes the transformation of the word sut’ from a verb to a noun. The prerequisites for such change existed in the early proto-Indo-European language, in which the 3rd person plural form of the verb acquired a different phonetic appearance due to the change *es → *s. Later the present tense forms of the verb byti gradually disappeared from the old Russian language. The verb jest’ became the universal form, which can syntactically express the present tense opposed to other tenses (U nego byla sobaka ‘he had a dog’ – U nego jest’ sobaka ‘he has a dog’ – U nego budet sobaka ‘he will have a dog’), as well as all three grammatical persons (U men’a jest’ sobaka ‘I have a dog’ – U teb’a jest’ sobaka ‘you have a dog’ – U nego jest’ sobaka ‘he has a dog’) and two grammatical numbers (U men’a jest’ sobaka ‘I have a dog’ – U nas jest’ sobaka ‘we have a dog’). The opposition of the forms jest’ and sut’, where jest’ represents a singular form and sut’ the plural one, remained the longest. It is still fixed in some modern grammars, such as “Russian grammar”, 1980, but it is not supported by any examples of modern usage. There were several indications that the word sut’ was used as a noun in the first half of the 18th century. However, they are not supported by convincing examples. Indisputable examples of using sut’ as a noun only appeared in the middle of the 19th century. In 1858 the word was fixed in the dictionary as a noun. In modern Russian language there is a noun sut’, while such verb doesn’t exist anymore. The way the verb sut’ has transformed into a noun proves how long and unpredictable the history of words in a language can be.