Il polpastrello rimane sul sensore.

Polpastrello is the soft pad of the fingertip, not the whole finger.

So:

• dito = finger
• punta del dito = tip of the finger
• polpastrello = the fleshy part you press onto a surface, such as a touchscreen or fingerprint sensor

In this sentence, that specific meaning matters because a sensore is something you touch or press with the fingertip.

Il is the masculine singular definite article, meaning the.

You need it because polpastrello is a singular masculine noun:

• il polpastrello = the fingertip

Italian uses articles more often than English does, especially in instructions, descriptions, and general statements. So even where English might sometimes sound more natural without an article, Italian usually keeps it.

Rimane is the third-person singular present of rimanere, which means to remain, to stay, or to keep being in a place/state.

The subject is il polpastrello, which is singular, so the verb must also be singular:

• io rimango
• tu rimani
• lui/lei rimane

So Il polpastrello rimane... means The fingertip remains/stays...

Yes. Resta from restare is also possible here, and in many contexts it sounds very natural.

Compare:

• Il polpastrello rimane sul sensore.
• Il polpastrello resta sul sensore.

Both can mean essentially the same thing: the fingertip stays/remains on the sensor.

A small nuance:

• rimanere can sound slightly more like remain
• restare can sound slightly more like stay

But in everyday Italian, they often overlap.

Because sul is the contracted form of su + il.

So:

• su + il = sul

This is very common in Italian. Some other examples are:

• a + il = al
• di + il = del
• in + il = nel
• da + il = dal

So sul sensore literally comes from on the sensor.

Because su means on, onto, or upon, and the fingertip is in contact with the surface of the sensor.

So:

• sul sensore = on the sensor

That is the natural preposition when something is touching the surface of something else.

They describe different relationships:

• sul sensore = on the sensor
• nel sensore = in the sensor

With a fingertip, sul sensore is correct because your fingertip touches the outside surface of the sensor, not the inside of it.

So Il polpastrello rimane sul sensore is the natural choice.

The normal, neutral order is:

• Il polpastrello rimane sul sensore.

That is the most natural version in most situations.

You can change the word order for emphasis, for example:

• Sul sensore rimane il polpastrello.

But that sounds marked or literary, and it would not usually be the best choice for a simple instruction or description.

So for learners, the standard order is the one to remember.

Grammatically, it is a statement, not a direct command.

It literally says that the fingertip remains/stays on the sensor.

However, in practical contexts such as device instructions, Italian sometimes uses statements to describe what should happen or what the user is expected to do. So depending on context, it may feel close to an instruction.

A more direct command would be something like:

• Tieni il polpastrello sul sensore. = Keep your fingertip on the sensor.
• Lascia il polpastrello sul sensore. = Leave your fingertip on the sensor.

Italian often uses the definite article where English prefers a possessive, especially with body parts.

So Italian commonly says:

• il polpastrello
• la mano
• gli occhi

where English may say:

• your fingertip
• your hand
• your eyes

In context, it is obvious whose fingertip is meant, so Italian does not need to say tuo.

A helpful approximation is:

pol-pa-STREL-lo

The stress is on strel.

A rough pronunciation guide for the whole sentence:

eel pol-pa-STREL-lo ree-MAH-neh sool sen-SO-reh

A few useful notes:

• ll in Italian is a normal l sound, not like English dark l
• r is usually tapped or lightly rolled
• final vowels are pronounced clearly

Yes. Sensore is masculine singular.

So you say:

• il sensore = the sensor
• un sensore = a sensor

And in the sentence:

• sul sensore = su + il sensore

That masculine article is why the contraction is sul.

Here it normally suggests a temporary state: the fingertip stays on the sensor for some period of time.

So the idea is not that the fingertip permanently belongs there, but that it continues to be there at that moment.

In instructions or device-related language, that often implies:

• keep it there
• do not lift it yet
• it is still in contact with the sensor

That is why rimane works well in this context.