A more thorough explanation:

Definition: At large means free, unrestrained, and not under control. It can also mean not limited to any particular place, person, matter, or question. In politics, it refers to being chosen by the voters of an entire political entity, such as a state, county, or city, rather than from separate districts within the entity. Additionally, it can mean not ordered in a topical way, at random, or fully and in detail.

• The suspect is still at large.
• The election for the councilmember at large is coming up.
• The book contains statutes at large, which are not ordered in a topical way.
• The professor discussed the issue at large, fully and in detail.

The first example illustrates the meaning of at large as being free and unrestrained. The suspect is not under control and is still on the loose. The second example shows how at large is used in politics to refer to being chosen by the voters of an entire political entity. The third example demonstrates how at large can mean not ordered in a topical way, as the statutes are not arranged in a specific order. The fourth example shows how at large can mean fully and in detail, as the professor discussed the issue in an extended form.