Bolul portocaliu este plin.

Because -ul is the Romanian definite article, meaning the.

• bol = a bowl
• bolul = the bowl

Romanian usually attaches the to the end of the noun instead of putting it in front like English does.

So:

• un bol portocaliu = an orange bowl
• bolul portocaliu = the orange bowl

Bol is a neuter noun in Romanian.

Romanian neuter nouns behave:

• like masculine in the singular
• like feminine in the plural

That matters because adjectives must agree with the noun. Since bolul is singular, its adjectives use the masculine singular form:

• portocaliu
• plin

So even though bol is technically neuter, in the singular it takes forms that look masculine.

In Romanian, adjectives usually come after the noun.

So:

• bolul portocaliu = the orange bowl

This is the normal order. English usually puts adjectives before the noun, but Romanian usually puts them after.

A learner often wants to translate word-for-word from English, but portocaliu bol would not be the normal form here.

Because the adjective must agree with bolul.

Since bol is a neuter noun and is singular, it uses the masculine singular adjective form. That is why you get:

• portocaliu = masculine/neuter singular
• portocalie = feminine singular

Examples:

• bol portocaliu = orange bowl
• farfurie portocalie = orange plate

So in this sentence, portocaliu matches bolul correctly.

For the same reason: plin must agree with the subject, bolul.

Here, plin is a predicate adjective after este (is), and it still agrees with the noun:

• bolul este plin = the bowl is full
• sticla este plină = the bottle is full

Because bolul is singular neuter, Romanian uses the masculine singular form plin.

Este means is. It is the 3rd person singular form of a fi (to be).

So:

• Bolul portocaliu este plin. = The orange bowl is full.

In standard Romanian, you normally keep it. In casual speech, people often shorten it to e:

• Bolul portocaliu e plin.

That is very common and natural in conversation.

You would say:

Bolurile portocalii sunt pline. = The orange bowls are full.

Notice how everything changes to agree with the plural noun:

• bolul → bolurile
• portocaliu → portocalii
• este → sunt
• plin → pline

This is a good example of how Romanian agreement works.

A useful English-style approximation is:

por-toh-kah-LYOO

The stress is on the last part: -liu.

A rough breakdown:

• por
• to
• ca
• liu

And bolul is roughly:

BO-lul

Romanian pronunciation is usually fairly consistent, so once you learn the sound patterns, words become easier to read aloud.

No. Here it is clearly a color adjective, meaning orange-colored.

In Romanian:

• portocaliu = orange (the color, adjective)
• portocală = orange (the fruit)

So bolul portocaliu means the orange bowl, not the bowl of oranges.

You usually use plin de + noun.

Examples:

• Bolul portocaliu este plin de apă. = The orange bowl is full of water.
• Bolul portocaliu este plin de fructe. = The orange bowl is full of fruit.

So plin by itself means full, and plin de ... means full of ....

Yes: it is a good example of how Romanian builds a definite noun phrase.

English says:

• the orange bowl

Romanian says:

• bolul portocaliu

So Romanian expresses definiteness on the noun itself (bolul) and then adds the adjective after it (portocaliu).

This pattern is very common and worth getting used to early:

• cartea interesantă = the interesting book
• scaunul verde = the green chair
• bolul portocaliu = the orange bowl