It is an informal construct that is used often in speech but rarely in writing. For example: Said in conversation: "she can't be late to her next meeting so she's got to leave by noon" Written in an email: "she can't be late to her next meeting so she needs to leave by noon" Said in conversation: "I've got 3 unused tickets if anyone wants one" Written in an email: "I have 3 unused tickets if anyone wants one"

Hello Evgeniia. It’s possible to say it either way, although much more common without “got” in this particular context. Explanation: First of all, we can ignore “every day” — the object is “class”, “I have class.” Your dictionary is correct: "We use have (got) to talk about possession, relationships, characteristics and illnesses." When we say that we “have five lessons”, the lessons are not something that we possess, and they are also not a relationship, a characteristic, or an illness. “To have lessons” is an expression meaning “to attend class” or “to study with a tutor”, or something like that. There is no possession. As another example, the idiomatic expression “to throw a party” means the same thing as to “have a party”, but we cannot say “to have got a party”.

I would write or speak "I have five lessons a week/per week." Here is a thorough explanation (from dictionary.com Usage Note) USAGE NOTE FOR GET For nearly 400 years, forms of get have been used with a following past participle to form the passive voice: She got engaged when she was 19. He won't get accepted with those grades. This use of get rather than of forms of to be in the passive is found today chiefly in speech and informal writing. In British English got is the regular past participle of get, and gotten survives only in a few set phrases, such as ill-gotten gains. In American English gotten, although occasionally criticized, is an alternative standard past participle in most senses, especially in the senses “to receive” or “to acquire”: I have gotten (or got ) all that I ever hoped for. Have or has got in the sense “must” has been in use since the early 19th century; often the have or has is contracted: You've got to carry your passport at all times. The use of have (or has ) got in the sense of “to possess” goes back to the 15th century; it is also frequently contracted: She's got a master's degree in biology. These uses are occasionally criticized as redundant on the grounds that have alone expresses the meaning adequately, but they are well established and fully standard in all varieties of speech and writing. In some contexts in American English, substituting gotten for got produces a change in meaning: She's got ( possesses ) a new job. She's gotten ( has aquired ) a new job. He's got to ( must ) attend the wedding. He's gotten to ( has been allowed or enabled to ) attend. The children have got ( are suffering from ) the measles. The children have gotten ( have caught ) the measles. The use of got without have or has to mean “must” ( I got to buy a new suit ) is characteristic of the most relaxed, informal speech and does not occur in edited writing except in representations of speech. Gotta is a pronunciation spelling representing this use.

It doesn't sound "incorrect", in fact, you will often hear native English speakers use the word "got" in this form of expression. But it is actually more grammatically correct to say: "I have 5 lessons a day" or "I have 5 lessons a day" Another example would be "I've got 2 dollars left after buying the tickets." You will hear that all the time from native English speakers. Although the more correct grammatical expression would be: "I have 2 dollars left after buying the tickets." Another example: Can I borrow a dollar? I haven't got enough. Can I borrow a dollar? I don't have enough. Only the most strict grammarian would correct you if you used "got" in this way in casual conversation.