Dictionary Forms of Nouns

When looking at a Latin dictionary, it is helpful to know how the dictionary lists its words. As discussed in Latin Sentence Structure, Latin nouns change endings based on their function in a sentence. Dictionary listings of Latin words can help one determine which endings those words use. Let's take, for instance, this dictionary listing for pecus, a Latin word for a cattle.

pecus, pecudis - (f.) cattle

First we see pecus. This is the nominative form of the noun, the form of the noun used when it is the subject of the sentence. Moreover, this is singular.

The next thing we see is pecudis, the genitive singular form of pecus. There are many uses for the genitive case, one of which being that it serves as a template for the other forms of pecus. One knowledgeable in Latin noun endings can determine from these two forms that the dative singular form of pecus will be pecudī, the accusative singular will be pecudem, the ablative singular will be pecude, and so forth. Don't worry if you don't understand what we're talking about here -- we will cover it soon. For now, just know that the second form listed here, the pecudis form, the genitive singular, is instrumental in figuring out what the other forms of the same noun is.

This manner of listing is also crucial when the dictionary lists two nouns that have the same nominative form. As an example, look at this dictionary listing for an equally valid alternate pecus.

pecus, pecoris - (n.) herd of cattle

These two nouns have very similar meanings and identical nominative singular forms. The only way we can distinguish between these nouns is the second dictionary form, the genitive singular. Whereas endings such as pecudis, pecudī, pecudem... tell us that we're referring to a cattle, endings derived from pecoris (pecorī, pecus, pecore...) tell us that we're referring to an entire herd of cattle.

So what about the next thing we see? In the first dictionary listing we have a (f.), and in the second one we have a (n.). What do those mean? Each Latin noun has a grammatical gender (which are separate from actual genders). These genders are masculine (m.), feminine (f.), and neuter (n.). Again, more on that later.

After all of that, we reach the end, which is our definition. Don't be surprised if the same word has more than one definition -- even when the definitions seem completely different.