Avia nepoti osculum dat.

• avia = the subject: the person doing the action
• nepoti = the indirect object: the person receiving something
• osculum = the direct object: the thing being given
• dat = the verb: gives

So the structure is:

subject + indirect object + direct object + verb

Because Latin often uses the dative case instead of a separate word like to.

• nepos = grandson
• nepoti = to/for the grandson

In this sentence, nepoti is dative singular, showing the recipient of the kiss.

English says:

• gives a kiss to the grandson

Latin can simply say:

• nepoti = to the grandson

without needing an extra word.

Osculum is the direct object, so it is in the accusative case.

A few useful details:

• osculum is a second-declension neuter noun
• for many neuter nouns, the nominative singular and accusative singular look the same
• so osculum can be either nominative singular or accusative singular in form

Here it is accusative singular because it is the thing being given: a kiss.

Dat comes from the verb dare, meaning to give.

The form dat tells you several things at once:

• present tense = gives / is giving
• third person
• singular
• active voice

So dat means:

• he gives
• she gives
• it gives

In this sentence, since avia is feminine, the natural English translation is she gives.

There is no separate word for she because Latin often leaves subject pronouns out when they are not needed.

The ending of dat already tells us the subject is:

• third person
• singular

Then avia tells us who that third-person singular subject is: the grandmother.

So Latin does not need a separate ea or another pronoun here.

We know mainly from case and sentence structure.

• avia is nominative singular, the normal case for the subject
• nepoti is dative singular, so it is not the subject
• osculum is accusative singular here, so it is also not the subject

That leaves avia as the word doing the action.

A small extra note: without macrons, avia could look ambiguous by itself in isolation, because first-declension forms can sometimes look alike in plain spelling. But in this sentence, the grammar makes its role clear: it is the subject.

Latin often puts the verb near the end of the sentence, especially in straightforward prose, but it does not always have to.

So Avia nepoti osculum dat is a very normal order.

Because Latin uses case endings, the word order is much more flexible than in English. For example, these can still mean basically the same thing:

• Avia nepoti osculum dat
• Osculum avia nepoti dat
• Nepoti avia osculum dat

The endings tell you who is giving, what is being given, and to whom.

Word order in Latin often changes for emphasis, not just grammar.

Yes. It is a perfectly normal and natural Latin expression.

Latin can express this idea with a noun plus dare:

• osculum dare = to give a kiss

English also uses this pattern, so it matches quite well.

There are other ways Latin can talk about kissing, but osculum dat is simple and idiomatic.

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

So:

• avia can mean grandmother or the grandmother
• nepoti can mean to a grandson, to the grandson, to her grandson, and so on, depending on context
• osculum can mean a kiss or the kiss

When translating into English, you choose a or the from the context.

Yes. The dative case often covers both ideas:

• to the grandson
• for the grandson

With dare, the most natural sense is usually to someone, because the person is receiving the thing given. So here to the grandson is the best basic understanding.

Still, it is good to remember that the Latin dative is broader than just one English preposition.