Buen provecho; la cena está lista.

Because buen is the shortened form of bueno used before a singular masculine noun.

• bueno = good
• provecho = benefit / enjoyment / nourishment

Since provecho is masculine singular, Spanish uses buen provecho.

Compare:

• un buen libro
• un buen día
• buen provecho

But after the noun, you would usually use bueno:

• El libro es bueno.

Provecho literally means something like benefit, good use, or nourishment. In the expression buen provecho, it does not translate word-for-word naturally into English. The whole phrase works like:

• Enjoy your meal
• Hope you enjoy your food

So it is best learned as a fixed expression rather than translated literally every time.

People usually say buen provecho:

• right before eating
• when serving food
• sometimes to people who are already eating

It is very common in Latin America. You may hear it from:

• family members
• restaurant staff
• coworkers
• even strangers passing by a table in some places

It functions a lot like enjoy your meal.

Yes. Buen provecho is very commonly used on its own.

Examples:

• ¡Buen provecho!
• Gracias, igualmente.

In your sentence, it is followed by another full clause:

• Buen provecho; la cena está lista.

So the first part is a set expression, and the second part gives extra information.

The accent mark in está shows the stressed syllable and also distinguishes it from esta.

• está = is from the verb estar
• esta = this or a feminine form of this one

Examples:

• La cena está lista. = The dinner is ready.
• Esta cena está rica. = This dinner is tasty.

So the accent is important both for pronunciation and meaning.

Spanish uses estar for states or conditions, and being ready is treated as a condition, not a permanent identity.

So:

• La cena está lista. = The dinner is ready.

If you used ser here, it would sound wrong.

Also, be careful: with people, ser listo/lista can mean clever, while estar listo/lista usually means ready.

Examples:

• Ella es lista. = She is clever.
• Ella está lista. = She is ready.

Because lista agrees with la cena, which is a feminine singular noun.

Agreement in Spanish:

• masculine singular: listo
• feminine singular: lista
• masculine plural: listos
• feminine plural: listas

Examples:

• El almuerzo está listo.
• La cena está lista.
• Las comidas están listas.

Yes. Here lista is an adjective meaning ready.

This is a very common point of confusion because lista can also be a noun meaning list in other contexts.

Compare:

• La cena está lista. = The dinner is ready.
• Tengo una lista de compras. = I have a shopping list.

So the meaning depends on the sentence structure.

In Spanish, the definite article is often used where English might or might not use the.

Here, la cena refers to the dinner / dinner as a specific meal already understood in the situation.

• La cena está lista.

In natural Spanish, dropping the article here would usually sound incomplete or unnatural.

The semicolon connects two closely related complete thoughts:

• Buen provecho
• la cena está lista

It is stronger than a comma and weaker than a period.

You could also write:

• Buen provecho. La cena está lista.

That would be completely natural too. The semicolon simply shows that the ideas are closely linked in writing.

A simple pronunciation guide is:

bwen pro-VE-cho; la SE-na es-TA LIS-ta

A few key points:

• buen sounds roughly like bwen
• provecho has the stress on ve
• cena in most of Latin America sounds like SE-na
• está is stressed on the second syllable: es-TA
• lista is stressed on the first syllable: LIS-ta

Usually, yes. Cena normally means dinner or the evening meal.

Related meal words:

• desayuno = breakfast
• almuerzo or comida = lunch, depending on the country
• cena = dinner

In most Latin American contexts, la cena está lista would naturally mean dinner is ready.

Yes. Ya often adds the sense of already.

• La cena está lista. = Dinner is ready.
• La cena ya está lista. = Dinner is already ready.

Adding ya can make the sentence feel a little more immediate or emphasize that the waiting is over.