Thraex parmam et ocream habet.

Thraex is in the nominative singular, the case normally used for the subject of a finite verb.

We know it is the subject because:

• habet is a singular verb
• the sentence needs someone who has
• parmam and ocream are in the accusative, so they are objects, not the subject

So Thraex is the one doing the having.

Because they are direct objects of habet.

Their dictionary forms are:

• parma
• ocrea

These are first-declension nouns. In the accusative singular, first-declension nouns usually change -a to -am:

• parma → parmam
• ocrea → ocream

So the -am ending shows that these are the things the gladiator has.

Et means and.

It joins parmam and ocream, showing that both nouns are objects of habet. In other words, the gladiator has both items.

Habet comes from the verb habeo, habere, meaning to have.

The ending -t tells you it is:

• third person
• singular
• present tense

So habet means he has, she has, or it has. Here, because the subject is Thraex, it means he has.

Latin does not have articles like English a, an, and the.

That means a noun like parmam can mean:

• a small shield
• the small shield

and the exact choice depends on context. Latin often leaves that for the reader or translator to supply.

Yes, the word order could be different.

Latin word order is more flexible than English because the endings show the grammatical roles. So these would still mean basically the same thing:

• Thraex parmam et ocream habet
• Parmam et ocream Thraex habet
• Thraex ocream et parmam habet

The version with habet at the end is very normal Latin style.

You would look them up under their dictionary forms:

• parmam → parma
• ocream → ocrea
• habet → habeo

That is because parmam and ocream are declined forms, and habet is a conjugated verb form.

• Thraex is masculine
• parma is feminine
• ocrea is feminine

The gender does not change their role in this sentence, but it matters elsewhere, especially when adjectives or pronouns refer to them.