З одного боку — передплата, з іншого боку — контракт.

It is a set contrast structure, like on the one hand ... on the other hand in English.

Literally, it comes from from one side ... from the other side, but in normal usage it often introduces two contrasting options, aspects, or considerations.

So in this sentence, it frames two opposing or alternative items:

• з одного боку — передплата
• з іншого боку — контракт

Because after з in this expression, Ukrainian uses the genitive case.

So:

• один → одного
• інший → іншого

These adjectives agree with боку, which is also in the genitive singular.

Бік is the dictionary form, the nominative singular.

After з, this expression uses the genitive singular, so:

• бік → боку

That is why you get:

• з одного боку
• з іншого боку

This is the normal fixed form of the expression.

It is best to treat it as a fixed expression.

A word-for-word breakdown is possible:

• з = from
• одного = one
• боку = side

But learners should really memorize:

• з одного боку = on the one hand
• з іншого боку = on the other hand

That will sound much more natural than trying to build it from scratch every time.

Because Ukrainian often omits є in the present tense when the meaning is clear.

So instead of saying something like:

• З одного боку є передплата, з іншого боку є контракт

it is very natural to say:

• З одного боку — передплата, з іншого боку — контракт.

The verb is / there is is understood.

The dashes mark a pause where English would often use a verb like is or there is.

They help separate:

• the framing phrase: з одного боку
• the item being presented: передплата

and then again:

• з іншого боку
• контракт

So the dash is doing some of the work that an omitted verb would do.

They are in the nominative singular.

Here they function as the main named items in each half of the sentence. Since the sentence is basically elliptical—without an explicit present-tense verb—the nouns stay in the nominative.

So:

• передплата = nominative singular
• контракт = nominative singular

It can mean different things depending on context.

Common meanings include:

• prepayment / advance payment
• subscription

So if you see передплата in a business or payment context, it may mean advance payment. In a media or service context, it may mean subscription.

The exact nuance depends on the situation, not just the word by itself.

They are close, but not always identical.

• договір is a broad general word for an agreement or contract
• контракт is also contract, but often sounds more specific, formal, or tied to a particular type of arrangement, such as employment or a formal business arrangement

In many contexts they overlap, but they are not always perfectly interchangeable.

You may hear similar forms in speech, but for this meaning the standard and most natural expression is:

• з одного боку ... з іншого боку

Using боку is the normal idiomatic choice when you mean on the one hand ... on the other hand.

With сторона, the phrase can sound more literal, less standard, or more colloquial depending on context.

Yes, Ukrainian word order is flexible, but this paired structure is often kept as a recognizable pattern.

The full repeated form:

• З одного боку — ..., з іншого боку — ...

is clear and natural.

You might rearrange parts for emphasis in other contexts, but for learners, this fixed pattern is the safest and most idiomatic one to use.