SEO Explained in One Sentence

Search Engine Optimization (SEO) is the process of driving organic traffic (non-paid) to your website by  a) finding the keywords with the highest search volumes that are related to what services you provide (i.e. extractions), and then b) strategically adding those keywords to the corresponding pages (i.e. the extractions page) in the appropriate areas  (<title> tag, page title, h1, h2, h3, text) while c) keeping the page readable for a human being (i.e. avoiding keyword stuffing).