رأس القطة صغير.

Because Arabic often uses nominal sentences in the present tense, and in those sentences there is usually no separate word for "is".

So:

• رأس القطة صغير = The cat’s head is small

In English, you must say is. In Arabic, you normally do not include it in a simple present-tense sentence like this.

Here is the breakdown:

• رأس = head
• القطة = the cat
• صغير = small

Grammatically:

• رأس القطة = the cat’s head
• صغير = the predicate/adjective describing it

So the full structure is:

• رأس القطة → the subject
• صغير → what is being said about the subject

This is because رأس القطة is an iḍāfa (ضافَة), often called a construct phrase.

In an iḍāfa:

• the first noun usually does not take الـ
• the second noun can be definite, and that makes the whole phrase definite

So:

• رأس قطة = a cat’s head / head of a cat
• رأس القطة = the cat’s head

Even without الـ on رأس, the whole phrase is definite because القطة is definite.

Because it means the cat, not just a cat.

The الـ is the Arabic definite article, like the in English.

So:

• قطة = a cat
• القطة = the cat

In this sentence, القطة is the second part of the iḍāfa, so it tells you whose head it is: the cat’s head.

Because صغير is describing رأس, not القطة.

And رأس is a masculine noun in Arabic.

So the agreement is:

• رأس → masculine
• adjective describing it → صغير

If the noun being described were feminine, you would expect the feminine form:

• صغيرة

But here the sentence means The cat’s head is small, not The cat is small. The thing that is small is the head, and head is masculine.

Yes. It is an iḍāfa phrase, and it functions as a single noun phrase.

So:

• رأس القطة = the cat’s head

Inside that phrase:

• رأس is the first term of the iḍāfa
• القطة is the second term, in a genitive relationship

Then the whole phrase is followed by:

• صغير = the predicate

So the sentence is basically:

• [The cat’s head] [is small]

In full formal grammar, it would usually be:

• رَأْسُ القِطَّةِ صَغِيرٌ

Case-wise:

• رأسُ → nominative, because it is the subject of the nominal sentence
• القطةِ → genitive, because it is the second noun in the iḍāfa
• صغيرٌ → nominative, because it is the predicate

In normal everyday writing, these short vowel endings are usually not written, so you typically just see:

• رأس القطة صغير

رأس is pronounced roughly like ra's or raʾs.

The symbol أ/ء here represents a hamza, a glottal stop. It creates a break between the vowel sounds.

So رأس is not pronounced like one smooth syllable such as raas. It has a slight stop in it:

• raʾs

That hamza is part of the spelling of the word.

The final ة is called tāʾ marbūṭa. It often marks a noun as feminine.

So قطة means cat as a feminine noun form, and القطة means the cat.

A useful detail:

• when pausing, ة is usually pronounced like -a
• in grammatical connection, especially with case endings, it can sound like -t

So in careful full pronunciation, you may hear something like:

• al-qiṭṭati

But in normal pause, learners often hear it more like:

• al-qiṭṭa

It is a complete sentence.

That is because it has:

• a subject: رأس القطة
• a predicate: صغير

Arabic does not need a present-tense is, so this is already a full sentence meaning:

• The cat’s head is small

If it were only the phrase رأس القطة, that would just mean:

• the cat’s head

But adding صغير makes it a full statement.

Yes, Arabic can sometimes vary word order, but رأس القطة صغير is the most straightforward and neutral order for learners.

This order is:

• subject first
• predicate second

That is the clearest way to say:

• The cat’s head is small

Other orders may be possible in some contexts, but they can sound more marked, literary, or context-dependent. For a beginner, رأس القطة صغير is the best pattern to learn.

No. رأس القطة صغير means:

• The cat’s head is small

If you want The small cat’s head, then small must describe the cat, not be the predicate of the sentence.

That would require a different structure, such as:

• رأس القطة الصغيرة

There, الصغيرة describes القطة inside the noun phrase.

So compare:

• رأس القطة صغير = The cat’s head is small
• رأس القطة الصغيرة = the small cat’s head

This is a very common and important distinction in Arabic.

Yes. That is the literal structure.

• رأس القطة = head of the cat

But in natural English, we usually say:

• the cat’s head

Both show the same relationship. Arabic expresses this relationship through iḍāfa, not with a word like of or an apostrophe.