La pistola está bajo la cama.

Because pistola and cama are both feminine singular nouns, so they take the feminine singular definite article la.

• la pistola = the pistol
• la cama = the bed

In English, the never changes, but in Spanish the article agrees with the noun’s gender and number.

A very common pattern in Spanish is that nouns ending in -a are feminine, and both pistola and cama follow that pattern.

So you learn them as:

• la pistola
• la cama

That said, the -a = feminine rule is only a tendency, not a guarantee, so it is best to learn nouns together with their article.

Because Spanish normally uses estar for location.

So when you say where something is, you usually use estar:

• La pistola está bajo la cama.
• El libro está en la mesa.

By contrast, ser is used more for identity, definition, and more permanent characteristics:

• La pistola es negra. = The pistol is black.
• Es un arma. = It is a weapon.

The accent mark shows both pronunciation and meaning.

• está = a form of estar
• esta = this, feminine

So the accent helps distinguish the verb form from another common word. It also shows that the stress falls on the last syllable: es-TÁ.

Yes. Both are correct.

• La pistola está bajo la cama.
• La pistola está debajo de la cama.

Both mean the same thing here. Bajo is a preposition meaning under, and debajo de means underneath or below.

In everyday Spanish, many speakers often prefer debajo de when talking about physical position, but bajo la cama is completely natural and correct too.

They are related, but not used in exactly the same way.

• bajo = under, below
  
  • bajo la cama
• debajo de = underneath, under
  
  • debajo de la cama
• abajo = down, downstairs, below in a more general sense
  
  • Está abajo. = It is downstairs / down below.

So in this sentence, bajo and debajo de work, but abajo by itself does not mean under the bed.

No. If you use debajo, you normally need de before the noun.

Correct:

• debajo de la cama

Not correct:

• debajo la cama

By contrast, bajo does not need de:

• bajo la cama

Yes, you can change it, but the basic neutral order is:

subject + verb + place

So:

• La pistola está bajo la cama.

You could also say:

• Bajo la cama está la pistola.

That version is more marked and sounds more like emphasis or a dramatic reveal, as if you are focusing on where it is.

Yes, if the context already makes it clear what you are talking about.

For example, if someone asks ¿Dónde está la pistola?, you can answer:

• Está bajo la cama.

Spanish often leaves out information that is already understood from the context.

No, not in normal Spanish.

You need the article here:

• bajo la cama

Without the article, it sounds incomplete or ungrammatical in standard usage. Since you are talking about a specific noun, cama, the article is needed.

A simple pronunciation guide is:

la pis-TO-la es-TÁ BA-ho la KA-ma

A few notes:

• pistola has the stress on TO
• está has the stress on the last syllable: TÁ
• bajo has a Spanish j sound, pronounced like a strong throaty h in Spain
• cama has the stress on KA

A rough IPA version is:

/la pisˈtola esˈta ˈbaxo la ˈkama/

Yes, it is natural in Spain.

A speaker in Spain could definitely say:

• La pistola está bajo la cama.

Many speakers might also say:

• La pistola está debajo de la cama.

Both are normal. The second one may sound a little more explicitly physical to some speakers, but the first is absolutely standard.

You would replace la cama with mi cama:

• La pistola está bajo mi cama.
• La pistola está debajo de mi cama.

Notice that Spanish does not say la mi cama here. The possessive mi replaces the article.