Uncia pars hereditatis est.

Latin often uses two nouns together to make the idea more precise.

• uncia = a twelfth
• pars = part

So uncia pars means something like a twelfth part or a one-twelfth share.

In other words, uncia tells you what kind of pars it is.

Both are nominative singular feminine.

That is because they go together as the main noun phrase of the sentence: uncia pars hereditatis.

You can think of this whole phrase as the thing being described by est.

• uncia: nominative singular
• pars: nominative singular

They match because they belong together.

Not exactly. Uncia is normally a noun, not an adjective.

Here it is being used with pars in a way that feels a bit adjectival in English, because English would often say a twelfth part or a one-twelfth share.

So grammatically in Latin, it is better to think of uncia as a noun used alongside pars, not as a regular adjective.

Hereditatis is genitive singular of hereditas.

The genitive is used because Latin says part of something with a genitive:

• pars hereditatis = part of the inheritance

This is a very common pattern in Latin. After words like pars, the thing being divided or referred to is often put in the genitive.

It is the genitive of the whole (often also called a partitive genitive).

That means:

• pars = a part
• hereditatis = of the inheritance, the whole from which the part comes

So the phrase means a part of the inheritance.

Latin does not have articles like English a, an, and the.

So uncia pars hereditatis est can be understood from context as:

• a twelfth part of the inheritance is ...
• or the twelfth part of the inheritance is ...

English has to choose an article, but Latin does not.

Latin word order is much more flexible than English word order.

Putting the verb at the end is very common, especially in straightforward prose. So:

• Uncia pars hereditatis est

is perfectly normal Latin.

English usually wants is earlier, but Latin often saves the verb for the end.

Yes. Latin endings, not word position alone, show how the words function.

So other orders could still be understandable, such as:

• Pars hereditatis uncia est
• Hereditatis pars uncia est

The exact emphasis may change, but the grammar is still clear because of the case endings.

Not here.

Uncia can mean things like a twelfth, and from that basic sense it can be used for units such as an ounce or an inch in other contexts.

But in this sentence, because it is joined with pars hereditatis, it clearly means a twelfth share or one-twelfth part, not the modern English idea of an ounce.

The dictionary form is hereditas, hereditatis.

This is a third-declension feminine noun.

So:

• nominative singular: hereditas
• genitive singular: hereditatis

That is why the form in the sentence ends in -is.

The sentence is built like this:

• uncia pars hereditatis = the noun phrase
• est = is

So the structure is basically:

[noun phrase] + [is]

A very literal breakdown would be:

• uncia = a twelfth
• pars = part
• hereditatis = of the inheritance
• est = is

So grammatically it is a simple statement with a linking verb.