Particularly when you're researching a topic for the first time, you will run across unfamiliar concepts and vocabulary. These concepts and terms often show up in peer-reviewed journal articles, since these sources are written by experts primarily for an expert audience. These authors may assume that the audience understands professional terminology.
If you're just starting to look at the peer-reviewed literature in a subject area, you might find it difficult to understand the ongoing scholarly "conversation," partly due to unfamiliar concepts. A critical researcher should learn to spot important concepts—sometimes it can be easy to gloss over them when you're reading quickly. When you read about an unfamiliar concept, you should look it up in a specialized encyclopedia, dictionary, or other reference source.
The reference collection on the first floor of Ekstrom includes many of these sources, which provide background information that will help you understand the concepts and vocabulary in peer-reviewed journals and other academic sources. To locate reference sources in your subject area, contact a librarian or explore relevant subject guides.