Some sites and search engines use very specific language, and definitions may help you target your search for what you need.
There are thousands of OERs on the web! You will be able to evaluate the content best, to find what works for your courses.
Here are some additional factors that can help evaluate OERs you find on the web:
An aggregated search is a search engine that looks through multiple other search engines. These are two of the largest OER aggregated or federated searches. Start with these two search engines to look through many major OER sites at once.
➔ The Mason OER Metafinder launches a simultaneous search across more than 20 different sources of open educational materials. Originally developed at George Mason University Libraries.
➔ Openly Available Sources Integrated Search (OASIS) launches a simultaneous search across more than 80 different sources of open educational materials. Originally developed at SUNY Geneseo's Milne Library.