Domnul este aici.

Because -ul is the Romanian definite article, equivalent to English the.

• domn = gentleman / man / sir / Mr.
• domnul = the gentleman / the man / the sir (depending on context, usually more naturally the gentleman or the man)

So in this sentence, domnul is the definite form of the noun.

Romanian usually puts the definite article at the end of the noun, not before it like English does.

So:

• băiat = boy
• băiatul = the boy
• domn = gentleman / sir
• domnul = the gentleman / the man

This is a very normal feature of Romanian grammar.

Domnul can have several related meanings, depending on context:

• the gentleman
• the man
• sir
• Mr. (before a name, as in domnul Popescu = Mr. Popescu)
• sometimes the Lord in religious contexts

In a simple sentence like Domnul este aici, it usually means the gentleman or the man unless the context makes something else clear.

Este means is. It is the 3rd person singular form of the verb a fi = to be.

So:

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

In this sentence, domnul este aici literally matches English very closely:

• domnul = the gentleman
• este = is
• aici = here

Normally, no. In standard Romanian, you usually keep the verb a fi in sentences like this.

So:

• Domnul este aici. = correct, standard
• leaving out este would usually sound incomplete in normal Romanian

However, in everyday speech, people very often use the short form e instead of este:

• Domnul e aici.

That is extremely common and natural.

Aici means here. It is an adverb, so it does not change for gender, number, or case.

It stays aici regardless of who or what is being talked about.

Examples:

• Sunt aici. = I am here.
• Cartea este aici. = The book is here.
• Domnul este aici. = The gentleman is here.

This is the most neutral, straightforward word order:

• Domnul este aici.

But Romanian word order is somewhat flexible. You can change it for emphasis or style.

For example:

• Este aici domnul.

This can sound more marked, as if emphasizing here or introducing the gentleman after the fact.

For a learner, Domnul este aici is the safest and most neutral version.

A simple English-friendly approximation is:

DOM-nool ES-teh ah-EECH

A few notes:

• Domnul: the o is a clear Romanian o, and the ending -ul sounds roughly like ool
• este: pronounced ES-te
• aici: roughly ah-EECH

The ci at the end of aici sounds like ch in English cheese, but a bit shorter and lighter.

It can, but only if the context is religious.

Romanian domn / Domnul can refer to:

• a gentleman / sir
• Mr.
• the Lord (religious meaning)

Since this sentence begins with Domnul, capitalization alone does not tell you which meaning is intended, because the first word of a sentence is capitalized anyway. You need context to know.

Yes, if the subject is already understood from context.

• Domnul este aici. = The gentleman is here.
• Este aici. = He/it is here.

Romanian often leaves out subject pronouns when they are understood, but nouns are only omitted when the listener already knows who or what you mean. So Este aici is fine in context, but Domnul este aici is clearer on its own.