Шайка стоит у двери.

Шайка is in the nominative singular. It is the subject of the sentence — the thing that is standing / located somewhere.

You can tell the verb agrees with it:

• шайка стоит = singular subject + singular verb

So the basic structure is:

• Шайка = the subject
• стоит = stands / is standing
• у двери = by the door

Because the preposition у requires the genitive case.

The noun дверь means door, and its genitive singular form is двери.

So:

• дверь = nominative
• у двери = by the door / near the door

This is very common in Russian:

• у дома = by the house
• у окна = by the window
• у двери = by the door

Here у means by, near, or at.

So у двери means:

• by the door
• near the door
• sometimes at the door, depending on context

It does not literally mean inside the door or on the door. It simply gives the location as being close to the door.

Russian normally does not use a present-tense word for is in simple sentences like this.

So instead of saying something like The tub is by the door, Russian often says something more like:

• The tub stands by the door or
• The gang is standing by the door

The verb стоять means to stand. In Russian, this verb is often used for:

• people who are on their feet
• objects that are upright or positioned somewhere

So стоит gives both:

1. the idea of location
2. the idea of standing/upright position

Yes, very often.

Russian commonly uses different position verbs for objects:

• стоять = to stand
• лежать = to lie
• сидеть = to sit
• висеть = to hang

For example:

• Книга лежит на столе. = The book is lying on the table.
• Лампа стоит на столе. = The lamp is standing on the table.
• Картина висит на стене. = The picture is hanging on the wall.

So if the thing in question is thought of as upright, стоять is natural.

Yes. Russian word order is fairly flexible.

This sentence could also be:

• У двери стоит шайка.

Both versions are grammatical.

The difference is usually about focus:

• Шайка стоит у двери. = starts with шайка, so the sentence is more about the tub / gang
• У двери стоит шайка. = starts with the location, so the sentence emphasizes where it is

English usually relies more on fixed word order, but Russian often uses word order to shift emphasis.

Because шайка is singular.

The verb must agree with the subject:

• шайка стоит = singular
• шайки стоят = plural

So if you changed the subject to plural, the verb would also change:

• Шайки стоят у двери.

Yes. Шайка is feminine.

You can see this from:

• the ending -а, which is typical of many feminine nouns
• the dictionary form being шайка

However, in the present tense, the verb form стоит does not show gender. It only shows:

• person
• number

Gender becomes visible in the past tense:

• шайка стояла = feminine
• стол стоял = masculine
• окно стояло = neuter

Yes. Шайка can have more than one meaning, depending on context.

Common meanings include:

• a gang
• a tub / basin in some contexts

So by itself, the word can be ambiguous. The correct meaning depends on the situation or on what meaning was already given to you.

Grammatically, though, the sentence works the same way either way:

• Шайка стоит у двери.

A simple pronunciation guide is:

• Шайка = SHAI-ka
• стоит = sta-EET
• у = oo
• двери = DVYE-ri

Approximate whole sentence:

• SHAI-ka sta-EET oo DVYE-ri

Stress:

• ша́йка
• стои́т
• две́ри

The stressed syllables are important in Russian, especially in words like стоит and двери.