Cheia poate fi oriunde.

Cheie is the basic dictionary form, meaning key.
Cheia means the key.

Romanian usually puts the definite article at the end of the noun instead of using a separate word like English the.

So:

• cheie = a key
• cheia = the key

Here, poate is the verb form of a putea = to be able to / can.

In this sentence, poate means can / may / could, because it is followed by fi.

Romanian also has poate as an adverb meaning maybe, but that is a different use. For example:

• Poate vine mâine. = Maybe he/she is coming tomorrow.

In Cheia poate fi oriunde, it is definitely the verb.

Because a putea is a modal verb, and in Romanian it is followed by the infinitive of the main verb.

So:

• poate = can
• fi = be

Together, poate fi = can be / could be / may be

This works much like English:

• The key can be anywhere.
• Cheia poate fi oriunde.

Oriunde usually means anywhere or wherever, depending on context.

In this sentence, it means anywhere.

It is an adverb of place, so it tells you where something may be.

Related words:

• unde = where
• undeva = somewhere
• nicăieri = nowhere
• oriunde = anywhere / wherever

In normal use, oriunde means anywhere, not everywhere.

So Cheia poate fi oriunde means the key could be in any place at all, not that it is in all places at once.

If you wanted everywhere, Romanian would use peste tot or pretutindeni, depending on style and context.

The neutral, most natural order is:

Cheia poate fi oriunde.

Romanian word order is fairly flexible, though. You can move things around for emphasis, especially in speech or literary style.

For example:

• Oriunde poate fi cheia.
  This is possible, but it sounds more marked or emphatic, like The key could be anywhere with extra focus on anywhere.

For a learner, the original order is the safest and most natural.

Not in this sentence.

Cheie is a feminine noun, but the verb forms here do not change for gender:

• cheia poate fi
• cartea poate fi
• masa poate fi

They all use the same poate fi.

Gender would matter more with adjectives or past participles in some contexts, but not here.

Not if you want the same meaning.

Cheia poate fi oriunde means The key could be anywhere / may be anywhere.

If you say Cheia este oriunde, it sounds wrong or very unnatural for this idea. Romanian needs the modal idea here: can/may/could be.

If you want a simple statement about location, you would normally say something like:

• Cheia este aici. = The key is here.
• Cheia este undeva în casă. = The key is somewhere in the house.

But for open possibility, poate fi is the right structure.

Yes. Cheia ar putea fi oriunde is also correct.

The difference is nuance:

• Cheia poate fi oriunde = The key can/may be anywhere
• Cheia ar putea fi oriunde = The key could be anywhere

The version with ar putea often sounds a little more tentative or hypothetical.

A rough English-style pronunciation is:

KEH-ya POA-te fee o-ree-OON-deh

A few notes:

• Cheia has two clear parts: chei-a, roughly KEH-ya
• poate is roughly POA-te
• fi is simply fee
• oriunde is roughly o-ree-OON-deh, with the stress on OON

As always, English spelling cannot show Romanian sounds perfectly, but this gets you close.

It is one word: oriunde.

Romanian writes it as a single word, just like several other indefinite forms built with ori-, such as:

• oricine = anyone / whoever
• orice = anything / whatever
• oricând = anytime / whenever
• oriunde = anywhere / wherever

Here are the base forms:

• cheia → cheie = key
• poate → a putea = to be able to / can
• fi → a fi = to be
• oriunde stays oriunde = anywhere / wherever

This is useful because Romanian dictionaries usually list nouns without the attached definite article, and verbs under the infinitive form.

Yes. Depending on context, poate fi can correspond to several English possibilities:

• can be
• may be
• could be

In this sentence, all of these can work, depending on the tone the translator wants. Romanian often leaves that exact shade of possibility to the context.