A cél a biztonságos kerékpár.

Because both noun phrases are definite:

• a cél = the goal
• a biztonságos kerékpár = the safe bicycle

In Hungarian, the predicate noun phrase can also have its own article. So this is normal grammar.

A useful contrast:

• A cél a biztonságos kerékpár. = The goal is the safe bicycle / the safe bike
• A cél egy biztonságos kerékpár. = The goal is a safe bicycle

So a suggests something definite, known, or treated as a specific category in context, while egy would make it indefinite.

In Hungarian, the verb van is usually omitted in present-tense third-person sentences like this when the predicate is a noun or adjective.

So:

• A cél a biztonságos kerékpár.
  literally has no spoken is, but in English you translate it with is

This is very common:

• Péter tanár. = Péter is a teacher.
• A ház nagy. = The house is big.

If you change the tense, the verb appears:

• A cél a biztonságos kerékpár volt. = The goal was the safe bicycle.

It is grammatical, but it may sound a little unusual without context.

The most direct reading is something like The goal is the safe bicycle, where the safe bicycle is being identified as the goal.

Depending on what you really want to say, Hungarian might more naturally use:

• A cél egy biztonságos kerékpár. = if the goal is to obtain a safe bicycle
• A cél a biztonságos kerékpározás. = if the goal is safe cycling

So a learner might want to remember that the given sentence is fine structurally, but the exact choice of words depends a lot on context.

Biztonságos means safe.

It is built from:

• biztonság = safety, security
• -os = a common adjective-forming suffix

So:

• biztonság → biztonságos
• safety → safe

This is a very common Hungarian pattern. The adjective simply comes before the noun:

• biztonságos kerékpár = safe bicycle

Not when it is used before the noun like this.

Hungarian adjectives usually do not agree with the noun in number when they are attributive:

• biztonságos kerékpár = safe bicycle
• biztonságos kerékpárok = safe bicycles

Notice that biztonságos stays the same.

But when the adjective is used as the predicate, it can show plural:

• A kerékpár biztonságos. = The bicycle is safe.
• A kerékpárok biztonságosak. = The bicycles are safe.

Yes, but the emphasis changes.

• A cél a biztonságos kerékpár.
  This presents the goal as the topic.

• A biztonságos kerékpár a cél.
  This shifts attention toward the safe bicycle.

Hungarian word order is much more about topic and focus than English word order is. So both can be grammatical, but they are not identical in emphasis.

Both are in the nominative form, the basic dictionary form.

That is because this is an equational sentence: one thing is being identified as another.

So you have:

• cél
• kerékpár

and not accusative forms like célt or kerékpárt.

For comparison:

• Látom a kerékpárt. = I see the bicycle.

Here kerékpárt has -t because it is the direct object. In A cél a biztonságos kerékpár, there is no direct object.

Hungarian has two forms of the definite article:

• a before a consonant sound
• az before a vowel sound

So here:

• a cél — c is a consonant
• a biztonságos kerékpár — b is a consonant

That is why a is used both times.

Examples with az:

• az autó = the car
• az ember = the person

A rough pronunciation guide is:

• A = a short aw
• cél ≈ tsayl
• biztonságos ≈ BIZ-ton-shaa-gosh
• kerékpár ≈ keh-RAYK-paar

A few useful pronunciation points:

• Hungarian stress is normally on the first syllable of each word.
• c is pronounced like ts
• s is pronounced like English sh
• sz is pronounced like English s
• é is a long ay/eh-like vowel
• á is a long open a

So the whole sentence is roughly:

aw tsayl aw BIZ-ton-shaa-gosh keh-RAYK-paar

English-style approximations are never perfect, but this will get you close.