Μην ξεχάσεις το τάπερ σου στο ψυγείο του γραφείου.

Μην is the negative particle used with this kind of verb form to make a negative command or prohibition.

So:

• Μην ξεχάσεις = Don’t forget

A useful thing to know is that in Modern Greek, negative commands are not usually formed with a special negative imperative form. Instead, Greek normally uses μη(ν) + subjunctive.

The dictionary form is ξεχνάω or ξεχνώ, meaning to forget.

In this sentence, ξεχάσεις is the 2nd person singular aorist subjunctive form.
That sounds technical, but the practical takeaway is:

• ξεχνάω / ξεχνώ = I forget / to forget
• να ξεχάσεις = for you to forget / that you forget
• μην ξεχάσεις = don’t forget

You may also notice the aorist stem ξεχασ- inside ξεχάσεις.

Because that is the normal way to make a negative command in Modern Greek.

Compare:

• positive command: Ξέχνα το = forget it
• negative command: Μην το ξεχάσεις = don’t forget it

So even though English just uses don’t + verb, Greek usually uses:

• μην + subjunctive

That is why ξεχάσεις appears here.

This is a very common question.

• Μην ξεχάσεις uses the aorist and usually refers to one complete event:
  Don’t forget it this time.
• Μην ξεχνάς uses the present and usually suggests a repeated, ongoing, or habitual idea:
  Don’t keep forgetting / Remember not to forget

In this sentence, Μην ξεχάσεις is the natural choice because it is about one specific thing: remembering to take your container from the office fridge.

τάπερ is a very common everyday Greek word for a plastic food container, often the kind used to carry lunch.

It comes from the brand name Tupperware, but in Greek it is often used as a general word, not just for that brand.

So το τάπερ σου usually means something like:

• your food container
• your lunch container
• sometimes simply your Tupperware

Greek normally keeps the definite article and then adds the possessive pronoun.

So:

• το τάπερ σου = literally the container your
• natural English: your container

This is completely normal Greek structure. You will see it everywhere:

• το βιβλίο μου = my book
• η φίλη σου = your friend
• το σπίτι μας = our house

Here, σου is the weak possessive form meaning your.

Because Greek weak possessive pronouns usually come after the noun they belong to.

So:

• το τάπερ σου = your container

This post-noun placement is standard in Greek. English speakers often expect the possessive to come before the noun, but Greek works differently here.

στο is a contraction of:

• σε + το = στο

Depending on context, σε can mean:

• in
• at
• to

So στο ψυγείο means in the fridge here.

You will see this contraction very often:

• στο σπίτι = in/to the house, at home
• στο γραφείο = in/to the office
• στο τραπέζι = on/at the table

After σε, Modern Greek uses the accusative case.

So in στο ψυγείο, ψυγείο is accusative.

However, ψυγείο is a neuter noun, and many neuter nouns have the same form in the nominative and accusative singular. So even though the case is accusative, the word still looks like ψυγείο.

Also, Greek uses σε + accusative for both:

• movement toward something
• location in/at something

So στο ψυγείο can mean to the fridge or in the fridge, depending on context. Here it clearly means in the fridge.

του γραφείου means of the office.

This is the genitive form of το γραφείο = the office.

So:

• το ψυγείο του γραφείου = the office’s fridge
• more natural English: the office fridge

Greek often uses the genitive where English uses either:

• of
• an apostrophe-s
• a noun used like an adjective

Compare:

• η πόρτα του σπιτιού = the door of the house / the house door
• το κλειδί του αυτοκινήτου = the car key

So στο ψυγείο του γραφείου means in the office fridge, not just in the office.

Yes. Greek word order is more flexible than English word order.

The sentence as given:

• Μην ξεχάσεις το τάπερ σου στο ψυγείο του γραφείου.

is a very natural, neutral way to say it.

But Greek can move parts around for emphasis. For example, you might also hear:

• Μην ξεχάσεις στο ψυγείο του γραφείου το τάπερ σου.

That sounds more marked and gives more emphasis to the location.

So the original order is probably the best one to learn first:

• Μην ξεχάσεις = don’t forget
• το τάπερ σου = your container
• στο ψυγείο του γραφείου = in the office fridge