Эти дома похожи.

Because эти is the plural form used before a noun.

• этот дом = this house
• эти дома = these houses

Это is different. It is often used as this/that is, or as a neuter demonstrative pronoun:

• Это дом. = This is a house.
• Это мои друзья. = These are my friends.

But when you directly modify a plural noun, you use эти:

• эти дома
• эти книги
• эти окна

So in Эти дома похожи, эти agrees with the plural noun дома.

Because дом has an irregular-looking but very common plural pattern.

• singular: дом
• plural: дома

Many masculine nouns in Russian form the plural in -а / -я instead of -ы / -и. This is something you generally have to learn word by word, although some patterns become familiar over time.

Other examples:

• город → города
• берег → берега
• поезд → поезда

So дома here means houses, not some other form you need to translate differently.

Here дома is nominative plural, because it is the subject of the sentence.

You can tell this from the whole phrase:

• эти дома = these houses

Since эти is plural and the sentence is about what these houses are like, дома is functioning as the subject.

A beginner may notice that дома can also be another form in other contexts, but here the grammar makes it clear:

• Эти дома похожи. → дома = nominative plural

In Russian, the verb to be is usually omitted in the present tense.

English says:

• These houses are similar.

Russian simply says:

• Эти дома похожи.

This is normal Russian grammar. Compare:

• Он врач. = He is a doctor.
• Они дома. = They are at home.
• Мы готовы. = We are ready.

If you talk about the past or future, forms of быть do appear:

• Эти дома были похожи. = These houses were similar.
• Эти дома будут похожи. = These houses will be similar.

Because похожи is the short form of the adjective, and short forms are commonly used as the predicate in sentences like this.

• Эти дома похожи. = These houses are similar.
• похожие дома = similar houses

So the difference is:

• похожие = full adjective form, usually used before a noun
• похожи = short adjective form, often used after the subject as the main description

Compare:

• Это похожие дома. = These are similar houses.
• Эти дома похожи. = These houses are similar.

This short-form pattern is very common with adjectives in predicative use, though not every adjective behaves the same way.

Normally, for this meaning, standard Russian prefers Эти дома похожи.

Using похожие here sounds unnatural in neutral standard Russian, because after the subject you usually want the short form in this kind of sentence.

So:

• Эти дома похожи. ✅ natural
• похожие дома ✅ natural
• Эти дома похожие. ⚠ usually not the normal choice here

A learner should strongly prefer похожи in this sentence pattern.

By itself, Эти дома похожи usually suggests that the houses are similar/alike, often understood as similar to each other or similar in some relevant way from context.

If you want to state explicitly what something is similar to, Russian often uses похож на / похожа на / похожи на:

• Этот дом похож на тот. = This house is similar to that one.
• Эти дома похожи на старые русские усадьбы. = These houses resemble old Russian estates.

So the sentence without на is fine, but the comparison target is left implicit.

The neutral word order is:

• Эти дома похожи.

That is the most natural basic version: subject + predicate.

Russian word order is flexible, so you may sometimes see another order for emphasis or style, such as:

• Похожи эти дома.

But that sounds marked or literary and would usually put special emphasis on похожи. For normal everyday use, stick with:

• Эти дома похожи.

The stress is:

• э́ти дома́ похо́жи

A rough pronunciation guide for an English speaker:

• э́ти ≈ EH-ti
• дома́ ≈ da-MAH
• похо́жи ≈ pa-KHO-zhi

A few useful notes:

• Unstressed о is reduced in pronunciation, so it may sound closer to a than a clear English o.
• The ж in похожи sounds like the s in measure.

So the whole sentence sounds roughly like:

• EH-ti da-MAH pa-KHO-zhi

It is an adjective, specifically the short plural form of похожий.

That can feel strange to English speakers because it works where English uses are + adjective:

• English: The houses are similar.
• Russian: Дома похожи.

So even though похожи is doing the main descriptive job in the sentence, it is not a verb. The present-tense to be is just omitted, and the short-form adjective carries the description.