Pelerina de ploaie este în rucsac.

Because pelerina is the definite form of pelerină.

In Romanian, the definite article is usually attached to the end of the noun, instead of being a separate word like English the.

• pelerină = a rain cape / a raincoat
• pelerina = the rain cape / the raincoat

So Pelerina de ploaie means the rain cape / the raincoat.

Literally, de ploaie means of rain, but in natural English it works like rain- or for rain.

So pelerină de ploaie is a type expression:

• pelerină = cape
• de ploaie = for rain / rain-

This is a very common Romanian pattern:

• ochelari de soare = sunglasses
• haină de iarnă = winter coat
• geantă de voiaj = travel bag

So de here does not show possession. It helps describe what kind of item it is.

Este is the 3rd person singular present form of a fi, which means to be.

So:

• eu sunt = I am
• tu ești = you are
• el/ea este = he/she is

In this sentence, este means is.

You will also often hear e instead of este in everyday Romanian:

• Pelerina de ploaie e în rucsac.

That is more conversational, while este sounds a bit fuller or more neutral/written.

Normally, no. In standard Romanian, you keep the verb a fi in this kind of sentence.

So this is correct:

• Pelerina de ploaie este în rucsac.
• Pelerina de ploaie e în rucsac.

But this is not standard as a full sentence:

• Pelerina de ploaie în rucsac.

English speakers sometimes wonder this because some languages drop the present-tense to be, but Romanian usually does not.

Because Romanian often uses a bare noun after a preposition in location expressions, where English would often use the.

So Romanian can say:

• în rucsac = in the backpack
• pe masă = on the table
• în buzunar = in the pocket

This is normal Romanian. The noun does not always need a visible definite article in these prepositional phrases.

So în rucsac can naturally mean in the backpack, especially when the backpack is already understood from context.

You can make it more explicit like this:

• într-un rucsac = in a backpack
• în rucsacul meu = in my backpack
• în rucsacul negru = in the black backpack

So the sentence you have, în rucsac, is somewhat context-based. Romanian often leaves that choice to the situation, while English more often forces you to choose a or the.

The given order is the most neutral and easiest for learners:

• Pelerina de ploaie este în rucsac.

Romanian word order is fairly flexible, though. You can move things around for emphasis.

For example:

• În rucsac este pelerina de ploaie. = emphasizes the location
• Pelerina de ploaie este în rucsac. = neutral statement

So yes, other orders are possible, but the version you have is the best default pattern to learn.

The two main special vowels here are:

• ă in pelerină
• î in în

A rough guide:

• ă sounds like a very short, unstressed uh
• î is a tighter, more central sound that English does not really have

Very approximate pronunciation of the whole sentence:

• pe-le-REE-na de PLOA-ye ES-te în rook-SAK

A few notes:

• rucsac is pronounced roughly rook-SAK
• ploaie sounds roughly like PLOA-ye
• în is short and nasal-free; do not pronounce it like English in

Not always exactly.

Pelerină de ploaie often suggests a rain cape, poncho, or loose outer layer for rain. In some contexts, though, it can be translated simply as raincoat.

Another Romanian word you may see is impermeabil, which often refers more specifically to a waterproof coat or raincoat.

So in many beginner contexts, pelerină de ploaie is translated as raincoat, but the Romanian term can be a bit more specific in feel.