Η ηλεκτρονική σήμανση είναι υποχρεωτική.

A word-for-word breakdown is:

• Η = the (feminine singular)
• ηλεκτρονική = electronic
• σήμανση = marking / labeling / signage / indication depending on context
• είναι = is
• υποχρεωτική = mandatory / compulsory

So the structure is basically:

The electronic marking/labeling is mandatory.

Because they are both feminine singular forms.

The noun σήμανση is a feminine singular noun, so any adjective connected to it must agree with it in:

• gender: feminine
• number: singular
• case: nominative here

So:

• ηλεκτρονικός = electronic (masculine)
• ηλεκτρονική = electronic (feminine)
• ηλεκτρονικό = electronic (neuter)

And similarly:

• υποχρεωτικός = mandatory (masculine)
• υποχρεωτική = mandatory (feminine)
• υποχρεωτικό = mandatory (neuter)

Even though υποχρεωτική comes after είναι, it still agrees with σήμανση.

Η is the feminine singular definite article, meaning the.

It is used because σήμανση is feminine singular:

• η σήμανση = the marking / the labeling

Greek usually uses the definite article more often than English does, especially with nouns in general statements. So Η ηλεκτρονική σήμανση... is a very natural Greek way to say Electronic marking... or The electronic marking..., depending on context.

Because grammatical gender in Greek is a property of the noun itself.
The word σήμανση happens to be feminine.

This does not mean the thing itself is biologically feminine. It is just a grammar category. Because σήμανση is feminine, the article and adjectives around it must also be feminine:

• η σήμανση
• ηλεκτρονική σήμανση
• σήμανση είναι υποχρεωτική

In this sentence, υποχρεωτική is a predicate adjective. It describes the subject η ηλεκτρονική σήμανση after the verb είναι.

This works just like English:

• The marking is mandatory.

Here, mandatory is an adjective describing marking, not an adverb.

So Greek uses:

• subject: Η ηλεκτρονική σήμανση
• verb: είναι
• predicate adjective: υποχρεωτική

Not always. είναι can mean is or are, depending on the subject.

Examples:

• Η σήμανση είναι υποχρεωτική. = The marking is mandatory.
• Οι οδηγίες είναι σαφείς. = The instructions are clear.

So είναι is used for both singular and plural in the present tense, third person.

Yes, Greek word order is more flexible than English word order.

The most neutral order here is:

• Η ηλεκτρονική σήμανση είναι υποχρεωτική.

But you may also see:

• Υποχρεωτική είναι η ηλεκτρονική σήμανση.

This puts more emphasis on υποχρεωτική.

Even though word order can change, the endings and article help show what belongs together, so Greek does not rely on word order as heavily as English does.

It is one noun phrase:

• ηλεκτρονική σήμανση = electronic marking / electronic labeling

Here, ηλεκτρονική directly modifies σήμανση.

So the sentence breaks into two main parts:

• Η ηλεκτρονική σήμανση = the subject
• είναι υποχρεωτική = what is being said about it

σήμανση is a somewhat broad word. Depending on context, it can mean things like:

• marking
• labeling
• signposting / signage
• indication
• tagging

So the exact English translation depends on the topic. For example, in an official or technical context, ηλεκτρονική σήμανση might refer to electronic labeling, electronic tagging, or electronic marking.

A learner often wants a single fixed translation, but with words like σήμανση, context matters a lot.

A rough pronunciation guide is:

ee ee-lek-tro-nee-KEE SEE-man-see EE-ne ee-po-hre-o-ti-KEE

A few useful notes:

• η is pronounced like ee
• ηλεκτρονική has the stress on the last syllable: ηλεκτρονική
• σήμανση has the stress on the first syllable: σήμανση
• είναι is usually pronounced something like EE-ne
• υποχρεωτική has the stress on the last syllable: υποχρεωτική

The accent mark shows which syllable is stressed.

For example:

• σήμανση → stress on σή
• είναι → stress on εί
• υποχρεωτική → stress on κή

Accent marks are very important in Greek spelling, and learners should pay attention to them early. They are not optional in normal writing.

You add δεν before the verb:

• Η ηλεκτρονική σήμανση δεν είναι υποχρεωτική.

So:

• δεν είναι = is not

This is the normal way to make a sentence negative in Greek.

In some special contexts, especially headings, labels, or very compressed style, Greek may omit the article. But in a normal full sentence, η is the natural choice:

• Η ηλεκτρονική σήμανση είναι υποχρεωτική.

So for everyday standard Greek, learners should keep the article here.

Yes, it sounds fairly formal or official, especially because of the word υποχρεωτική and the technical phrase ηλεκτρονική σήμανση.

It sounds like something you might read in:

• regulations
• official instructions
• product requirements
• legal or administrative texts

It is perfectly normal Greek, but it has a formal, informational tone rather than a casual conversational tone.