The differences between "viruses" and "malware." Viruses are a specific type of malware (designed to replicate and spread), while malware is a broad term used to describe all sorts of unwanted or malicious code.
Malware can include viruses, spyware, adware, nagware, trojans, worms, and more. However, because viruses (and to a lesser extent, trojans and worms) made headlines a few years ago, most security companies focused their marketing on them, which is why they're called "antivirus."
Note: Malware like Trojans, Worms, Backdoors, Exploits, Adware, and PUP (Potentially Unwanted Programs), which can include communication clients, remote desktops and password revealers
https://www.malwarebytes.com/mwb-download/
https://security.symantec.com/nbrt/npe.aspx
https://www.microsoft.com/en-us/download/malicious-software-removal-tool-details.aspx?id=16
