De afspraak is op maandag.

Because afspraak is a de-word in Dutch. Dutch nouns have two grammatical article types:

• de for common-gender nouns
• het for neuter nouns

So the correct form is:

• de afspraak
• not het afspraak

Unfortunately, you usually have to learn whether a noun takes de or het along with the noun itself.

Afspraak often means appointment, but it can be a bit broader than that. Depending on context, it can also mean:

• an arranged meeting
• an agreement
• a date or planned occasion

In De afspraak is op maandag, the most natural meaning is the appointment / arranged meeting is on Monday.

So English appointment is a good translation here, but afspraak is slightly more flexible than that.

Dutch main clauses usually follow the verb-second rule, often called V2. That means the finite verb comes in the second position of the sentence.

In this sentence:

• De afspraak = first element
• is = verb in second position
• op maandag = rest of the sentence

So the structure is perfectly normal Dutch word order.

In Dutch, days of the week commonly use the preposition op when you mean on a certain day.

So:

• op maandag = on Monday
• op dinsdag = on Tuesday

You do not say in maandag.

You may sometimes hear just maandag without op, especially in speech, for example:

• De afspraak is maandag.

That is also possible in many contexts, but op maandag is very clear and standard.

It can mean different things depending on context.

In a sentence like:

• De afspraak is op maandag.

it usually means the appointment is on Monday — a specific Monday understood from context.

But in other sentences, op maandag can also mean on Mondays in a habitual sense, especially if the sentence is about routine:

• Ik werk op maandag. = I work on Mondays / on Monday

If you want to be extra specific about a single upcoming Monday, Dutch often uses expressions like:

• aanstaande maandag = next Monday
• komende maandag = coming Monday

In Dutch, days of the week are normally written with a lowercase letter, unlike in English.

So Dutch writes:

• maandag
• dinsdag
• woensdag

not:

• Maandag
• Dinsdag
• Woensdag

The same is true for months and many adjectives of nationality/language in Dutch. They are usually lowercase unless they begin the sentence.

More or less, yes. Dutch zijn can be used to locate something in time as well as in identity or state.

So:

• De afspraak is op maandag.

literally uses is, just like English The appointment is on Monday.

This is normal in Dutch. It does not sound strange or unnatural.

Yes, you can. That sentence is grammatical.

• Op maandag is de afspraak.

Because Dutch uses the verb-second rule, if op maandag comes first, then is still has to come second.

This version puts more emphasis on Monday, as if contrasting it with another day.

Compare:

• De afspraak is op maandag. = neutral
• Op maandag is de afspraak. = emphasis on Monday

A helpful approximation is:

• afspraak ≈ AHF-spraak

More precisely:

• the first part af sounds like ahf
• spraak has a long aa sound, somewhat like the vowel in British father, followed by k

Rough IPA:

• afspraak /ˈɑf.spraːk/

The stress is on the first syllable: AF-spraak.

A rough pronunciation is:

• maandag ≈ MAAN-dakh

Notes:

• maan has a long aa sound
• the final g in standard Dutch is a throaty sound, not a hard English g

Rough IPA:

• maandag /ˈmaːn.dɑx/

Stress is on the first syllable: MAAN-dag.

Yes, potentially. Afspraak can mean both a concrete appointment and an agreement, depending on context.

For example:

• We hebben een afspraak. can mean We have an appointment / arrangement
• Dat is de afspraak. can mean That is the agreement

But in De afspraak is op maandag, the time expression op maandag strongly suggests a scheduled event, so appointment or meeting is the most likely meaning.

Days of the week usually do not take an article in expressions like this.

So Dutch says:

• op maandag = on Monday

not:

• op de maandag in this normal sense

You may see de maandag in special contexts, but that is not the usual way to talk about the day of the week in a sentence like this.