This second paragraph of the article clarifies this. The largest ever fire was last year's August Complex. It was called a complex because it was a merger of se

This second paragraph of the article clarifies this. The largest ever fire was last year's August Complex. It was called a complex because it was a merger of several smaller fires. This fire is the largest ever "single fire" (having a single source) and the second largest fire of any kind (single or complex).