Questions & Answers about Mater cito domum redibit.
Because mater is the subject of the sentence: mother is the one doing the action.
It is in the nominative singular, which is the case Latin normally uses for the subject. Mater is a third-declension noun, and its nominative singular happens to look like this.
So in Mater cito domum redibit, mater means mother or the mother as the subject.
Latin has no articles. There is no ordinary word that directly corresponds to English the or a/an.
So mater can mean:
- mother
- a mother
- the mother
Which one is best depends on the context. The same is true for domum, which can be understood as home or the home, depending on the situation.