Термін дії платіжної картки — один рік.

In Ukrainian, the verb to be in the present tense is usually omitted.

So this sentence literally has the structure:

Термін дії платіжної картки — один рік
= The validity period of the payment card is one year

The dash marks the pause where English would use is. This is very common in formal or written Ukrainian, especially when one noun phrase is being identified or defined by another.

You could think of it as:

X — Y = X is Y

Because картки is in the genitive singular.

The phrase is:

платіжної картки = of the payment card

Here, термін дії means term/period of validity, and then Ukrainian adds the thing whose validity is being discussed:

• термін дії документа = validity period of the document
• термін дії договору = term of the contract
• термін дії картки = validity period of the card

So картки answers the idea of what? That is why it is not nominative картка.

Because adjectives must agree with the noun they describe.

The base form is:

• платіжна картка = payment card

But in the sentence, картка becomes genitive singular картки, so the adjective must also become genitive singular:

• платіжної картки

This is normal adjective-noun agreement in Ukrainian.

A quick comparison:

• нова картка = a new card
• номер нової картки = the number of the new card

So платіжної matches картки in case, number, and gender.

Literally, it is something like term of validity or period of effect/validity.

In real usage, it means:

• validity period
• expiration period
• sometimes simply how long something remains valid

This phrase is very common in official, banking, legal, and administrative language.

Examples:

• термін дії паспорта = passport validity period
• термін дії візи = visa validity period
• термін дії картки = card validity period

So дії here does not mean physical action in the everyday sense. It refers to something being in force / valid / effective.

Both are possible in some contexts, but один рік is more explicit: one year.

• один рік = one year
• рік = a year / year

In a formal statement like this, один рік clearly gives the exact duration.

Also, Ukrainian often uses the numeral even where English might sometimes just say a year.

Because this part of the sentence is functioning as the predicate: it tells us what the term is.

So the structure is basically:

Термін дії ... — один рік
= The validity period ... is one year

Here один рік stays in the nominative form.

Forms like одного року would appear in other grammatical environments, not in this simple equational sentence.

For example:

• немає одного року = there is no one year
• до одного року = up to one year

But here the sentence is simply identifying the duration, so один рік is the expected form.

Yes. Строк дії and термін дії are both used and often mean nearly the same thing: validity period / term.

That said, there can be stylistic differences:

• термін often sounds a bit more administrative or standard in many official contexts
• строк is also very common, especially in legal or formal language

In many everyday practical situations, both would be understood.

It is a correct and standard formal term meaning payment card.

Depending on context, Ukrainian speakers may also say more specific things such as:

• банківська картка = bank card
• кредитна картка = credit card
• дебетова картка = debit card

So платіжна картка is a broad, formal term. It fits well in official or banking-style language.

Yes, Ukrainian word order is fairly flexible, but not every version sounds equally natural.

The given sentence:

Термін дії платіжної картки — один рік

is very natural and neutral, especially in formal writing.

You might also see:

Один рік — термін дії платіжної картки

but that sounds more emphatic or stylistically marked, as if focusing on one year.

For a learner, the original order is the best one to remember.

A practical approximation is:

Termin diyi platizhnoji kartky — odyn rik

A few pronunciation notes:

• і sounds like ee in see
• и is a different vowel, shorter and more central than English ee
• й is like y in boy or yes, depending on position
• г in Ukrainian is usually a softer sound than English g
• картки is pronounced with a clear k sound before the final syllable

If you want to say it smoothly, group it like this:

Термін дії | платіжної картки | один рік

with a pause where the dash is.

It is absolutely real Ukrainian, but it sounds formal and official.

You would expect this kind of sentence in:

• bank documents
• contracts
• application forms
• official instructions
• technical descriptions

In casual speech, people might say something simpler depending on context, but the sentence itself is natural and standard in formal usage.