A more thorough explanation:

Duodena

Duodena means a group of twelve of anything.

• A carton of eggs usually contains a duodena of eggs.
• There are duodena inches in a foot.
• The jury in the trial was made up of a duodena of people.

The examples show that duodena refers to a group of twelve of anything. In the first example, a carton of eggs usually contains twelve eggs. In the second example, there are twelve inches in a foot. In the third example, the jury in the trial was made up of twelve people.