chuāngkǒu zài nàbiān.

Because 在 is the normal verb for showing where something is located.

• 窗口在那边。 = The window is over there.
• Literally: window + be located at + that side

Chinese usually uses 在 for location, not 是.

Compare:

• 窗口在那边。 = The window is over there.
• 窗口是新的。 = The window is new.

So 是 links a subject to a noun or adjective-like idea, while 在 tells you location.

那边 means over there, that side, or in that area.

It is made of:

• 那 = that
• 边 = side, edge, area

So 那边 is a natural way to point to a general place that is not near the speaker.

It is slightly less precise than a specific location like 房间里 (in the room), but very natural in everyday speech when pointing or indicating direction.

Chinese often follows this pattern for location sentences:

thing/person + 在 + place

So here:

• 窗口 = the window
• 在 = is located at
• 那边 = over there

This is one of the most basic Chinese sentence patterns.

Examples:

• 书在桌子上。 = The book is on the table.
• 老师在教室里。 = The teacher is in the classroom.
• 窗口在那边。 = The window is over there.

Normally, no.

是 does not usually connect a thing directly to a location. A location is usually introduced with 在.

So:

• correct: 窗口在那边。
• unnatural/wrong in normal Mandarin: 窗口是那边。

If you want to say where something is, use 在.

Both can be related to window, but they are not always identical.

• 窗户 usually means the physical window in everyday speech.
• 窗口 can also mean a window, but it often has extra meanings such as:
  • a service window/counter
  • a window opening
  • a metaphorical window/opportunity/interface

In some contexts, 窗口 can sound a little more formal or specific than 窗户.

So for a literal house window, many learners will hear 窗户 very often. But 窗口 is still a real word and can definitely be used depending on context.

Yes, in many everyday situations that would sound very natural.

If you are talking about an ordinary physical window in a room, 窗户在那边 is probably the more common casual phrasing.

So both can work, but 窗口 and 窗户 are not always interchangeable in every context.

Yes, often you can.

These are all related but slightly different:

• 那边 = over there / that side / that area
• 那里 = there
• 那儿 = there (more colloquial, especially in northern speech)

So these are all possible:

• 窗口在那边。
• 窗口在那里。
• 窗口在那儿。

Difference in feeling:

• 那边 often suggests direction or area
• 那里 / 那儿 are more straightforwardly there

If someone is pointing across a room, 那边 sounds especially natural.

Chinese does not have articles like a, an, and the.

So 窗口 can mean:

• a window
• the window

The exact meaning depends on context.

If the meaning has already been shown to the learner, then in context it probably means the window. But Chinese does not need a separate word for the.

Not here.

Measure words are used mainly with numbers, demonstratives, and sometimes quantifiers.

Examples:

• 一个窗口 = one window
• 那个窗口 = that window

But in 窗口在那边。, 窗口 is just the subject of the sentence, so no measure word is needed.

Pinyin:

• chuāngkǒu
• zài
• nàbiān

Tones:

• chuāng = 1st tone
• kǒu = 3rd tone
• zài = 4th tone
• nà = 4th tone
• biān = 1st tone

A natural rhythm is:

chuāngkǒu zài nàbiān

A few pronunciation notes:

• chuāng starts with ch, which is a retroflex sound, not like English ch exactly.
• kǒu has the ou sound, roughly like koh but not exactly English.
• zài sounds like dzai rather than English z-eye.
• biān is one syllable, not bee-an.

In this sentence, it is best understood as the main verb meaning to be located at.

So:

• 窗口 = subject
• 在 = verb
• 那边 = location

Chinese grammar books sometimes discuss 在 as both a verb and a preposition depending on the sentence, but for learners, in this sentence it is easiest and most useful to treat it as the verb to be at / to be located at.

Normally, no.

窗口那边。 by itself is not a normal complete sentence for The window is over there.

You need 在 to connect the subject to the location:

• 窗口在那边。

Chinese often allows omission in conversation, but for a standard full sentence, keep 在.

Not necessarily very far away. It just means that side / over there, usually away from the speaker.

It could refer to:

• across the room
• outside the door
• in that general direction
• somewhere not right here

So it shows distance relative to the speaker, but not always a large distance.

A very common way is to add 吗:

• 窗口在那边吗？ = Is the window over there?

You can also ask with a question word:

• 窗口在哪边？ = Which side is the window on?
• 窗口在哪里？ = Where is the window?

Notice that in these question forms, the basic location pattern stays the same.

It is neutral and very natural.

• 窗口在那边。 sounds like normal spoken or written Mandarin.
• If you use 窗户在那边。, that may sound even more everyday if you mean a literal household window.

So the sentence is simple, standard, and useful in ordinary conversation.