El contenedor de posos está lleno.

Posos means grounds, dregs, or sediment left behind after a liquid has been made or poured.

In this sentence, it most commonly refers to coffee grounds, especially in the context of a coffee machine. So contenedor de posos is the grounds container or used-coffee container.

A few useful notes:

• el poso = the residue/sediment left at the bottom
• los posos = grounds/dregs in general
• In coffee-machine Spanish, posos is very common.

Because lleno describes a state or condition, not a permanent characteristic.

In Spanish:

• ser is used for identity, classification, and more permanent qualities
• estar is used for states, conditions, and results

A container being full is a temporary condition, so Spanish uses estar:

• está lleno = is full

Compare:

• La caja está vacía = The box is empty
• La puerta está abierta = The door is open

So El contenedor de posos está lleno is the natural choice.

Because lleno has to agree with contenedor, which is:

• masculine
• singular

So:

• el contenedor → lleno
• la caja → llena
• los contenedores → llenos
• las cajas → llenas

This is standard adjective agreement in Spanish.

Here de means something like for, of, or used for, depending on how natural it sounds in English.

So:

• contenedor de posos = container for grounds / grounds container

Spanish often uses noun + de + noun where English prefers a compound noun:

• taza de café = coffee cup
• máquina de café = coffee machine
• contenedor de posos = grounds container

So this structure is very normal.

Because Spanish often leaves out the article after de when talking about something in a general/category sense.

So:

• contenedor de posos = container for grounds / grounds container

If you said de los posos, it would sound more like of the grounds, referring to specific grounds already mentioned.

Compare:

• una taza de café = a cup of coffee
• el sabor del café = the taste of the coffee

In your sentence, posos is being used generically, so no article is needed.

Yes, contenedor is a normal and understandable word in Spain, especially in appliance instructions or machine messages.

Depending on the device or context, you might also see:

• depósito
• recipiente
• cajón

But contenedor de posos sounds perfectly natural, especially in technical or appliance-related Spanish.

In a full sentence, yes, El is normal because contenedor is a countable noun and needs a determiner here.

So:

• El contenedor de posos está lleno = The grounds container is full

In some appliance screens, labels, warnings, or shortened instructions, Spanish may drop words for brevity, for example:

• Contenedor de posos lleno
• Vaciar contenedor de posos

But as a complete standard sentence, El is correct.

Yes, grammatically you could, and it would mean The grounds container is full of grounds.

But in practice, it is often unnecessary because contenedor de posos already tells you what kind of container it is. So está lleno is usually enough.

That is why the shorter version sounds more natural in many real-life contexts, especially on machine displays.

Here it is functioning as an adjective meaning full.

In está lleno, Spanish treats lleno as a descriptive word agreeing with the noun:

• El vaso está lleno
• La botella está llena

You do not need to analyze it as a verb form to use it correctly here. For learners, the key pattern is simply:

• estar + lleno/a(s) = to be full

In most of Spain, lleno is pronounced approximately like:

• YEH-no

The ll sound is usually pronounced like y in modern Spanish for most speakers.

So the whole sentence sounds roughly like:

• el kon-te-ne-DOR de PO-sos es-TA YEH-no

A few pronunciation notes:

• está has stress on the second syllable: es-TA
• contenedor has stress on the last syllable: dor
• lleno has stress on the first syllable: LLE-no

Yes, but the original order is the most neutral and natural.

Standard order:

• El contenedor de posos está lleno.

Other orders are possible for emphasis, but they are less neutral:

• Está lleno el contenedor de posos.

That sounds more marked or context-dependent, not the usual default for a machine message or straightforward statement.

So for normal use, stick with:

• El contenedor de posos está lleno.

Very often, yes.

In everyday use, posos strongly suggests:

• coffee grounds
• the used coffee residue collected by an espresso or coffee machine

So this sentence is exactly the kind of message you might see when a machine wants you to empty the used-grounds container.

That is why the sentence may sound more technical or appliance-specific than something you would say in casual conversation about an ordinary household container.