Этот прямоугольный ковёр лучше подходит для гостиной, а квадратный — для маленькой спальни.

Because ковёр is a masculine singular noun in the nominative case.

In Russian, words that describe a noun must agree with it in:

• gender
• number
• case

So here:

• ковёр = masculine, singular, nominative
• этот = masculine singular nominative form of this
• прямоугольный = masculine singular nominative form of rectangular

They all match:

• этот ковёр
• прямоугольный ковёр

If the noun were feminine, the forms would change:

• эта прямоугольная комната

Russian often leaves out a noun if it is obvious from context.

So:

• Этот прямоугольный ковёр = This rectangular carpet
• а квадратный — для маленькой спальни = and the square one is for a small bedroom

The word ковёр is understood after квадратный. In full, it would be:

• а квадратный ковёр — для маленькой спальни

But Russian often omits repeated nouns to avoid sounding repetitive.

The dash marks an omitted word, usually something like подходит here.

The full sentence could be understood as:

• Этот прямоугольный ковёр лучше подходит для гостиной, а квадратный лучше подходит для маленькой спальни.

Since подходит is repeated, Russian often leaves it out in the second part and uses a dash:

• а квадратный — для маленькой спальни

This is very natural in written Russian.

Подходит means suits / fits / is suitable.

Лучше подходит means is better suited or fits better.

So the sentence is making a comparison:

• the rectangular carpet is better for the living room
• the square one is better for the small bedroom

Here:

• хорошо = well
• лучше = better

So лучше подходит literally means suits better.

Подходить для + genitive means:

• to be suitable for
• to work well for
• to be a good fit for

Examples:

• Это подходит для кухни. = This is suitable for the kitchen.
• Этот цвет подходит для спальни. = This color works for the bedroom.

In your sentence:

• подходит для гостиной
• для маленькой спальни

So для introduces what something is suitable for.

Because both come after для, which requires the genitive case.

But the exact endings depend on the noun’s gender and declension.

1. для гостиной

The base form is гостиная = living room. After для, it becomes genitive:

• гостиная → гостиной

2. для маленькой спальни

The base form is маленькая спальня = small bedroom. In the genitive:

• маленькая → маленькой
• спальня → спальни

So both phrases are in the genitive, but they look different because the nouns belong to different declension patterns.

Yes, it originally looks like an adjective, and historically it comes from an adjective meaning something like guest-related.

But in modern Russian, гостиная is a normal noun meaning living room / sitting room.

This happens in Russian quite a lot: an adjective becomes a noun because the noun it originally described is omitted.

So learners should treat гостиная here simply as a feminine noun:

• гостиная = living room
• в гостиной = in the living room
• для гостиной = for the living room

А often contrasts two things, while и usually simply adds information.

Here the sentence compares two carpets and two rooms:

• the rectangular one is better for the living room,
• whereas the square one is for the small bedroom.

So а is a good choice because it means something like:

• while
• whereas
• and on the other hand

Using и would sound more like simple addition, not contrast.

Because маленькой agrees with спальни, which is:

• feminine
• singular
• genitive

The base adjective is:

• маленькая = small

In feminine singular genitive, it becomes:

• маленькой

So:

• маленькая спальня = a small bedroom
• для маленькой спальни = for a small bedroom

Again, adjectives must match the noun they describe.

Yes.

• прямоугольный = rectangular
• квадратный = square

These are standard adjectives for shapes.

Examples:

• прямоугольный стол = rectangular table
• квадратная комната = square room
• квадратный ковёр = square carpet

Notice how the endings change depending on the noun:

• квадратный ковёр — masculine
• квадратная комната — feminine
• квадратное окно — neuter

Yes, Russian word order is more flexible than English word order, but the original version sounds natural and clear.

The sentence:

• Этот прямоугольный ковёр лучше подходит для гостиной, а квадратный — для маленькой спальни.

puts the focus first on the two carpets, then on which room each suits.

You might see slight variations, but not all would sound equally natural. For example, moving лучше or the room phrases can shift emphasis.

For learners, the given order is a very good model:

• [item] + лучше подходит + для + [place]

Yes, it could mean either in English, depending on context.

Russian has no articles, so:

• для маленькой спальни can mean
  • for a small bedroom
  • for the small bedroom

The exact interpretation depends on the situation, not on a separate word like a or the.

That is very common in Russian:

• для кухни = for a kitchen / for the kitchen
• в комнате = in a room / in the room

Ковёр is a very common word and can mean:

• carpet
• rug

The exact English translation depends on context.

In home/furniture contexts, ковёр often refers to a carpet or rug placed on the floor.

So in this sentence, ковёр is exactly the normal word you would expect.