SEO (search engine optimization) – is the process of affecting the visibility of a website or a web page in a search engine.
SEM (search engine marketing) – is a form of Internet marketing that involves the promotion of websites by increasing their visibility in search engine results pages.
PPC/CPC (pay per click) is an internet advertising model used to direct traffic to websites, in which advertisers pay the publisher when the ad is clicked.
SEP (search engine positioning) is to describe the ordering process of indexed websites being ranked by a search engine algorithm in response to a query and use of search engine optimization to achieve a higher search engine position.
All this will be increasing your website rank and many users will come to see your website.
Those are the number of searches recorded since 2004 on Google for SEM vs. PPC vs. CPC.
The SEM does not always include SEO.
Can you see the relation between keywords: SEM >= PPC + CPC here.