Optimization means improving your website to perform better in some measurable way — usually referring to speed, but also commonly used in the context of SEO, or making content more search-engine friendly.
Performance Optimization
This usually involves compressing images, enabling caching, minimizing unnecessary plugins, and choosing solid hosting. The goal is a site that loads quickly for visitors, which also happens to be something search engines factor into rankings.
SEO Optimization
This focuses on making your content easier for search engines to understand and rank well — clear headings, descriptive titles, relevant keywords, and useful meta descriptions all play a part.
Where to Start
If you’re not sure where to begin, running a basic audit of your site’s speed and SEO fundamentals is a reasonable first step, since it highlights the most impactful issues before you spend time on smaller details.