El farolillo es nuevo.

Because farolillo is a masculine singular noun in Spanish, so it takes the masculine singular definite article el.

A good way to tell here is the ending: farolillo ends in -o, which is often masculine in Spanish. That is not a perfect rule, but it works in this case.

So:

• el farolillo = the lantern
• not la farolillo

Farolillo is a noun meaning a small lantern or little lamp/lantern, depending on context.

It comes from farol (lantern) plus the diminutive ending -illo, which often adds the idea of smallness. In Spain, farolillo can also refer to the decorative lanterns often seen at fairs or festivals.

So the word is not just a random vocabulary item: it is built like this:

• farol = lantern
• farolillo = small lantern / little lantern

Es is the third-person singular form of the verb ser, meaning is.

Here it matches the subject el farolillo, which is singular:

• el farolillo = singular
• es = is

So:

• El farolillo es nuevo. = The lantern is new.

Spanish often uses ser for a basic characteristic or description, and estar for a condition or state.

In El farolillo es nuevo, nuevo is being used as a general description: the lantern is a new one.

That is why ser sounds natural here.

However, estar nuevo also exists and can mean something like to be in brand-new condition. So there is a nuance:

• Es nuevo = it is new
• Está nuevo = it looks/feels brand new; it is in like-new condition

In many everyday contexts, both can appear, but es nuevo is the more straightforward way to say that the object is new.

Because adjectives in Spanish usually agree with the noun in gender and number.

Here:

• farolillo is masculine
• farolillo is singular

So the adjective must also be masculine singular:

• nuevo

Compare:

• el farolillo nuevo = the new lantern
• la lámpara nueva = the new lamp
• los farolillos nuevos = the new lanterns
• las lámparas nuevas = the new lamps

In El farolillo es nuevo, nuevo comes after the verb because it is part of the predicate:

• El farolillo = subject
• es = verb
• nuevo = description after the verb

This is different from placing the adjective directly next to the noun:

• el farolillo nuevo = the new lantern
• el farolillo es nuevo = the lantern is new

So here, nuevo is not simply modifying the noun inside a noun phrase; it is completing the meaning of the verb ser.

Yes, grammatically you can, but it usually means something different.

• El farolillo es nuevo = The lantern is new
  This usually refers to a specific lantern.

• Un farolillo es nuevo = A lantern is new
  This sounds less natural on its own unless you are introducing one lantern in a larger context.

For example:

• Mira los farolillos: el rojo es viejo y el verde es nuevo.
• He comprado un farolillo. Es nuevo.

So el is more natural if you are talking about a particular lantern already known from context.

Yes. Farolillo contains the diminutive ending -illo.

In Spanish, diminutives often express:

• small size
• affection
• sometimes a softer or more familiar tone

So:

• farol = lantern
• farolillo = little lantern / small lantern

In Spain, -illo is a common diminutive ending, though -ito is also very common in Spanish generally.

A simple approximation is:

fa-ro-LEE-yo

Some notes:

• r is a tapped Spanish r
• ll in most of Spain is pronounced like y in yes
• the stress falls on li: faroLILlo

A rough English-friendly guide:

• fa as in father
• ro
• LEE
• yo

Pronunciation can vary by region, but that is a good standard pronunciation for modern Spain Spanish.

Yes, very often.

Spanish frequently drops subject pronouns, and sometimes even the noun itself if the context is clear. So if everyone already knows you are talking about the lantern, you can simply say:

• Es nuevo. = It is new.

But if you want to identify the thing clearly, you keep the noun:

• El farolillo es nuevo.

Yes. It is a very standard and natural Spanish sentence pattern:

• Article + noun + verb + adjective

So:

• El farolillo = the subject
• es = the verb
• nuevo = the description

This is one of the most common basic sentence patterns in Spanish, especially for simple descriptions.