Every industry has its alphabet soup of acronyms, and marketing is no different. You may have heard the acronyms SEO and SEM thrown around interchangeably over time; tune into this #MarketingMonday segment to learn the differences between the two terms and which marketing method is appropriate for which occasions.
This was pretty much helpful; Haha! often times people do interchange SEO and SEM. Anyway, to make it simple: SEO is part of SEM. Search engine marketing (SEM) is a broad term while Search Engine Optimization (SEO) is just like a technique or a method. I hope this simple explanation I have provided is helpful as well.