Scholarly sources is an ambiguous term that gets thrown around often during the research process. In most cases, when your instructor asks you to find/use "scholarly sources" they are referring to articles in scholarly journals, which are sometimes referred to as peer-reviewed journals or academic journals.
The terms scholarly journal, academic journal, and peer-reviewed journal are all synonymous and interchangeable.
Additionally, "popular sources" refers, in large part, to articles found in magazines and newspapers.
The chart below compares/contrasts popular and scholarly sources:
You can sometimes find scholarly journal articles through Google, but there is often a hefty fee to obtain them. Your best bet is to check the Library's databases, where access to everything is FREE. You can start by finding sources through OneSearch, the big search bar on the Library's homepage (directions for finding scholarly articles this way can be found on the Finding Articles page of this guide). For suggestions on which databases to use after OneSearch, please refer to the More Ways to Search page of this guide.