Sol meridie altior est quam mane.

Sol is nominative singular, because it is the subject of the sentence: the thing being described.

• sol = the sun
• altior est = is higher

So Sol altior est means The sun is higher.

Meridie is the ablative singular of meridies, meridiei (midday, noon).

Here it means at midday or at noon. Latin often uses the ablative of time when for expressions of time, especially without a preposition.

So:

• meridie = at midday

This is a very common Latin pattern:

• prima luce = at first light
• nocte = at night
• aestate = in summer

Because Latin often does not need a preposition for time when.

In English we usually say at noon or in the morning, but Latin can simply use the ablative:

• meridie = at noon
• hora tertia = at the third hour
• hieme = in winter

So the lack of a preposition is normal Latin idiom, not a missing word.

Mane means in the morning.

It is commonly treated as an indeclinable adverb in this kind of usage. So unlike meridie, it is not functioning here as a regular noun in a visible case form. It simply tells when something happens.

So:

• meridie = at midday
• mane = in the morning

A learner may notice that both are translated similarly in English, but in Latin they are not built in exactly the same way.

Altior is the comparative form of altus (high, deep, depending on context).

So:

• altus = high
• altior = higher

Latin usually forms the comparative by adding -ior for masculine/feminine and -ius for neuter.

Examples:

• clarus → clarior = brighter / more famous
• longus → longior = longer
• altus → altior = higher

In this sentence, altior agrees with Sol, so it is masculine nominative singular.

Quam means than and introduces the second part of a comparison.

So:

• altior ... quam ... = higher ... than ...

In this sentence:

• Sol meridie altior est quam mane
• The sun is higher at midday than in the morning

Latin uses quam very much like English uses than after a comparative adjective.

The sentence compares the sun’s height at two different times:

• meridie = at midday
• mane = in the morning

So the full sense is:

• The sun is higher at midday than it is in the morning.

Latin does not have to repeat sol or est in the second part. English often does not repeat everything either:

• The sun is higher at midday than in the morning.

So the comparison is not the sun vs. the morning. It is the sun at midday vs. the same sun in the morning.

Est is the present tense of esse (to be), so it means is.

It links the subject Sol with the predicate adjective altior:

• Sol ... altior est = The sun is higher

In normal prose, including est is perfectly standard. In some kinds of Latin, especially poetry, forms of esse may be omitted when the meaning is clear, but in a straightforward sentence like this, est is exactly what you would expect.

Latin word order is more flexible than English word order because Latin shows grammatical relationships through endings, not mainly through position.

This sentence could be rearranged in several ways without changing the basic meaning, for example:

• Sol meridie altior est quam mane
• Meridie sol altior est quam mane
• Sol altior est meridie quam mane

The chosen order is natural and clear. Often Latin places words to highlight emphasis or rhythm rather than following a fixed English-style order.

They do have special endings, but altior is exactly the correct masculine nominative singular form here.

Comparative adjectives decline a bit like third-declension adjectives:

• masculine/feminine nominative singular: -ior
• neuter nominative singular: -ius

So:

• masculine/feminine: altior
• neuter: altius

Because sol is a masculine noun, the adjective must agree with it:

• sol altior
• not sol altius

Sometimes, yes. Latin can compare things in two main ways:

1. comparative + quam
2. comparative + ablative

For example:

• Marcus altior est quam Lucius = Marcus is taller than Lucius
• Marcus altior est Lucio = Marcus is taller than Lucius

But in this sentence, quam mane is the natural choice, because mane is an adverbial time expression, not a noun in the ablative being compared as a person or thing. So quam works very smoothly here:

• altior est quam mane = is higher than in the morning

Grammatically, meridie is a noun form: the ablative singular of meridies. But in the sentence it functions adverbially, because it tells when the action or state applies.

That is very common in Latin: a noun in a certain case can behave like an adverbial expression.

So you can think of it in two ways at once:

• form: ablative singular noun
• function: time expression meaning at midday

By itself, the sentence most naturally sounds like a general truth:

• The sun is higher at midday than in the morning.

Latin often uses the present tense this way for general facts. Nothing in the sentence limits it to one particular day, though context could do that if needed.