Learn Hardcore Latin: Familia luciferum nondum viderat, cum caelum clarum factum est. - The family had not yet seen the morning star when the sky became bright.

In Latin, familia is a singular noun. It refers to the household or family as one unit, so it takes a singular verb: viderat, not a plural form.

This is similar to English when we say the family was eating rather than the family were eating, depending on style.

Why does luciferum end in -um?

Because luciferum is the direct object of viderat and so it is in the accusative singular.

A beginner might expect -um to mean neuter, but that is not always true. Here luciferum can be masculine accusative singular from lucifer. So the ending is showing its job in the sentence, not necessarily that it is neuter.

What is the job of nondum in the sentence?

Nondum is an adverb meaning not yet. It modifies the verb viderat.

So luciferum nondum viderat means had not yet seen the light-bringer / morning star.

Latin adverbs often stand near the verb, but their position is fairly flexible.

Why is viderat translated as had seen instead of saw?