Stolryggen støtter korsryggen.

In Norwegian, the definite article is often attached to the end of the noun.

• stolrygg = chair back / backrest

• stolryggen = the chair back / the backrest

• korsrygg = lower back
• korsryggen = the lower back

So instead of writing a separate word like English the, Norwegian often adds -en, -a, or -et to the noun.

It is a compound noun:

• stol = chair
• rygg = back

So:

• stolrygg = chair-back
• stolryggen = the chair-back

This is very common in Norwegian. Instead of using a phrase like the back of the chair, Norwegian often prefers one compound word.

Because both are singular definite nouns of the common gender class in Bokmål.

The pattern is:

• en stolrygg = a chair back

• stolryggen = the chair back

• en korsrygg = a lower back
• korsryggen = the lower back

So -en here marks definite singular.

støtter is the present tense of the verb å støtte.

• å støtte = to support
• støtter = supports / is supporting

Examples:

• Jeg støtter deg. = I support you.
• Stolryggen støtter korsryggen. = The backrest supports the lower back.

In Norwegian, the present tense often ends in -er.

No, this is the normal basic word order:

• Stolryggen = subject
• støtter = verb
• korsryggen = object

So it follows a standard Subject–Verb–Object pattern, much like English:

• The chair back supports the lower back.

Because korsrygg is more specific. It refers to the lower back or lumbar area, not the whole back.

• rygg = back
• korsrygg = lower back

So korsryggen tells you exactly which part of the back is being supported.

Historically, yes, the first part is related to kors, but as a learner, the important thing is that korsrygg is a fixed anatomical word meaning lower back.

You do not normally need to interpret it literally every time. It is best learned as one vocabulary item:

• korsrygg = lower back

Yes, that is possible.

• ryggen på stolen = the back of the chair

But stolryggen is shorter and often more natural because Norwegian likes compound nouns.

So both can work, but:

• Stolryggen støtter korsryggen.
  is compact and very idiomatic.

The key sound here is ø, which does not exist in standard English.

A rough guide:

• ø is a rounded front vowel
• It is somewhat similar to the vowel in French deux or German schön

For støtter:

• the tt shows that the vowel before it is short
• so støtter has a short ø sound

Also:

• rygg has a short y sound
• gg makes the vowel short there too

You do not need perfect pronunciation immediately, but it helps to notice that doubled consonants in Norwegian often signal a short preceding vowel.

It would be:

• En stolrygg støtter en korsrygg.

Grammatically, that means:

• A chair back supports a lower back

But in real usage, the definite version often sounds more natural when talking about a specific function or general design:

• Stolryggen støtter korsryggen.

In Bokmål, it is usually simplest to say they are common gender nouns, since Bokmål commonly uses the article en with them:

• en stolrygg
• en korsrygg

So for practical learning:

• learn them with en
• definite singular becomes -en

That gives you:

• stolryggen
• korsryggen

Yes, it is grammatical and natural. It sounds like something you might see in a description of ergonomics, furniture design, posture, or office chairs.

It is also a nice example of several useful Norwegian features at once:

• compound nouns
• definite suffixes
• present tense in -er
• normal subject–verb–object word order