Za tydzień mamy rodzinny obiad u babci.

Za tydzień most literally means in a week / a week from now.

Polish uses za + accusative to talk about how much time will pass before something happens:

• za godzinę = in an hour
• za dwa dni = in two days
• za tydzień = in a week
• za miesiąc = in a month

In everyday English, the sentence might be translated as Next week we’re having a family lunch/dinner at Grandma’s, but grammatically za tydzień is specifically in a week.

Because za in this time expression takes the accusative case.

The noun tydzień is masculine inanimate, and in the singular its accusative form is the same as its nominative form:

• nominative: tydzień
• accusative: tydzień

So after za, you still see tydzień.

Compare with other nouns where the form changes more clearly:

• za godzinę = in an hour
• za minutę = in a minute

In Polish, the present tense is very often used for a planned or scheduled future event, just like in English:

• Tomorrow we’re meeting Anna.
• Next week we’re having a family meal.

So:

• Za tydzień mamy rodzinny obiad u babci.

sounds natural because it suggests an arranged plan.

You could say będziemy mieć, but in this kind of sentence it often sounds less natural or less idiomatic than simple mamy.

It can function as either, depending on context, but here it means something like:

• we’re having
• we have planned
• we’ve got

So mamy rodzinny obiad is not just about possession. It means there is an event arranged: we’re having a family meal.

Polish usually drops subject pronouns when they are not needed, because the verb ending already shows who the subject is.

• mam = I have
• masz = you have
• mamy = we have

So mamy already tells you the subject is we.

You can say my mamy, but that adds emphasis, for example:

• My mamy rodzinny obiad, a oni nie.
  We are having a family meal, and they aren’t.

Without emphasis, plain mamy is more natural.

It is in the accusative, because it is the direct object of mamy.

However, with a masculine inanimate noun like obiad, the accusative singular looks the same as the nominative:

• nominative: rodzinny obiad
• accusative: rodzinny obiad

So the form does not visibly change here, even though grammatically it is accusative.

Rodzinny means family / familial, and obiad is a main meal of the day, often eaten around midday or in the afternoon.

So rodzinny obiad means a family meal, often something like:

• a family lunch
• a family dinner
• a family get-together over a meal

A small cultural note: obiad does not map perfectly onto English lunch or dinner. Depending on the household and context, translators may choose either one.

U + genitive is commonly used to mean at someone’s place / at someone’s home / at someone’s place of business.

So:

• u babci = at Grandma’s
• u mamy = at Mum’s
• u lekarza = at the doctor’s

In this sentence, u babci means the family meal is taking place at Grandma’s house/place.

Because u requires the genitive case.

The noun changes like this:

• nominative: babcia = grandma
• genitive: babci = of grandma / at grandma’s (after u)

So:

• u babci = at Grandma’s

This is a very common pattern with u.

Yes, you could say w domu babci, and it means in Grandma’s house / at Grandma’s house.

But u babci is shorter and very natural in Polish when you mean at Grandma’s place.

So:

• u babci = natural, everyday
• w domu babci = also correct, a bit more explicit

Its primary meaning is location: the meal takes place at Grandma’s place.

In practice, that very often implies Grandma is involved, but grammatically the phrase itself mainly tells you where the event is happening.

The given word order is natural:

• Za tydzień mamy rodzinny obiad u babci.

But Polish word order is fairly flexible. You could also say:

• Mamy za tydzień rodzinny obiad u babci.
• U babci mamy za tydzień rodzinny obiad.
• Rodzinny obiad u babci mamy za tydzień.

These versions shift emphasis or sound more marked. The original sentence is the most neutral and natural for everyday use.

Putting za tydzień first gives the time expression a natural topic position: it sets the scene before the main information.

English often does the same:

• Next week, we’re having a family meal at Grandma’s.

So the sentence begins with the time frame, then tells you what is happening.

No. Polish has no articles like a, an, or the.

So rodzinny obiad can mean:

• a family meal
• the family meal

Which one is meant depends on context. In this sentence, English would usually say a family meal or just family lunch/dinner, depending on style.

Yes. Obiad is one of those words that does not line up perfectly with English meal words.

In many Polish contexts, obiad is the main cooked meal of the day, often eaten in the afternoon. Depending on the family’s habits and the translator’s choice, it may be rendered as:

• lunch
• dinner
• a meal

So you should learn the Polish word as a cultural meal category, not as a perfect one-word match for English.

No, not by itself.

Mamy here simply means we have / we’re having in the sense of a plan or arranged event. It does not express obligation.

If you wanted we have to, Polish would normally use something like:

• musimy = we must / we have to

So:

• Za tydzień musimy iść do babci. = We have to go to Grandma’s in a week.

That is different from the original sentence.

They could work in different styles, but they change the tone.

• Za tydzień mamy rodzinny obiad u babci.
  natural, conversational: We’re having a family meal at Grandma’s in a week.

• Za tydzień będzie rodzinny obiad u babci.
  more like: There will be a family meal at Grandma’s in a week.

• Za tydzień odbędzie się rodzinny obiad u babci.
  quite formal, almost event-like: A family meal will take place at Grandma’s in a week.

For normal everyday speech, mamy is the most natural choice.