La veta de la madera queda debajo del barniz.

In this sentence, veta means the grain or natural pattern in the wood.

So la veta de la madera = the grain of the wood.

A veta can also mean a vein in other contexts, such as:

• una veta de oro = a vein of gold

But with madera, it clearly means wood grain.

Quedar is often used in Spanish to mean to remain, to be left, or to end up located in a certain place.

Here, queda debajo del barniz suggests:

• the grain ends up
• remains
• or is left visible/located under the varnish

So queda sounds a bit more natural than a simple está in this context, especially when talking about how something is positioned after a process, such as applying varnish.

Compare:

• La veta está debajo del barniz. = The grain is under the varnish.
• La veta queda debajo del barniz. = The grain ends up / remains under the varnish.

Both are possible, but queda fits the idea especially well.

De la madera means of the wood or the wood’s.

In Spanish, this structure is very common:

• la puerta de la casa = the door of the house
• el color del coche = the colour of the car

Here, la veta de la madera means the grain of the wood, referring to the grain belonging to that wood.

If you said veta de madera, that would sound more general, like wood grain as a type of thing, not necessarily the grain of a specific piece of wood.

Because de + el contracts to del in Spanish.

So:

• de + el barniz → del barniz

This is a mandatory contraction.

Two very common contractions in Spanish are:

• a + el = al
• de + el = del

But this only happens with el, not with la, los, or las:

• de la madera ✔
• de el barniz ✘
• del barniz ✔

Both can mean under or below, but debajo de is often more common and more explicit for physical location.

In this sentence:

• debajo del barniz = under the varnish / beneath the varnish

You could also see:

• bajo el barniz

That is also correct, but debajo de often feels a bit more concrete when talking about physical position.

Very roughly:

• debajo de = underneath, beneath
• bajo = under, beneath, sometimes more concise or slightly more formal/literary depending on context

Spanish uses definite articles (el, la, los, las) more often than English does.

Here:

• la veta = the grain
• la madera = the wood
• el barniz = the varnish

English sometimes drops the, but Spanish often keeps it.

For example:

• Me duele la cabeza = My head hurts
• La madera es cara = Wood is expensive / The wood is expensive

So the articles in this sentence are completely normal.

Primarily it describes location: the grain is under the varnish.

But in context, it often also suggests that the grain is still visible through the varnish, because wood grain is something you normally see beneath a transparent finish.

So grammatically it means location, but practically it may imply that the varnish covers the wood while the grain still shows underneath.

Yes. That is a very literal translation and it matches the grammar well.

Depending on context, possible English versions include:

• The wood grain is under the varnish.
• The grain of the wood remains beneath the varnish.
• The wood grain lies beneath the varnish.

A learner should know that queda often does not need to be translated word-for-word every time. Natural English may simply use is.

The structure is:

• La veta de la madera = subject
• queda = verb
• debajo del barniz = prepositional phrase showing location

So:

[subject] + [verb] + [location]

More literally:

• The grain of the wood
  • remains/is left
    • under the varnish

Yes, depending on meaning.

Examples:

• Las vetas de la madera quedan debajo del barniz.
  The wood grain patterns remain under the varnish.
• La veta de la madera queda debajo de los barnices.
  This is grammatically possible, but less likely unless you are talking about different coats or types of varnish.

In the original sentence, singular works naturally because it refers to:

• the grain as a general feature
• the wood as a material or specific piece
• the varnish as the coating

Not always.

Spanish can use:

• la veta to refer to the grain as a general visible pattern
• las vetas to refer to individual streaks, lines, or markings in the wood

So both are possible:

• La veta de la madera es bonita. = The wood grain is beautiful.
• Las vetas de la madera son muy marcadas. = The grain lines/markings in the wood are very pronounced.

In your sentence, the singular sounds natural because it treats the grain as one overall feature.

Yes, that is grammatically correct.

The difference is mainly one of nuance:

• está = simply states where it is
• queda = suggests where it ends up or remains

So:

• está debajo del barniz = is under the varnish
• queda debajo del barniz = remains / ends up under the varnish

If you are just describing a finished object, both can work. Queda may sound a bit more idiomatic in descriptions of appearance or result.

In standard Spanish pronunciation, roughly:

de-BA-ho del bar-NEETH in much of Spain

A more helpful breakdown:

• debajo → de-BA-jo
• del → del
• barniz → bar-NIZ

In Spain, z is usually pronounced like th in thin, so:

• barniz sounds like bar-neeth

Also, the j in debajo is a strong guttural sound, like the ch in Scottish loch or German Bach, not an English j.