Google Search Console (GSC) helps webmaster and SEO expert to learn search queries that are generating traffic on the website, alerts on site related issues like crawling, indexing, and mobile usability.

Simply put together it provides information about how the site is performing in google search, helps with tools and analytics to make your website shine in google search results i.e. to bring more relevant traffic.

Glossary: Here's a short glossary of important terms

Index - Google stores all web pages that it knows about in its index. The index entry for each page describes the content and location (URL) of that page. To index is when Google fetches a page, reads it, and adds it to the index.

Crawl - The process of looking for new or updated web pages. Google discovers URLs by following links, by reading sitemaps, and by many other means. Google crawls the web, looking for new pages, then indexes them (when appropriate).

Crawler - Automated software that crawls (fetches) pages from the web and indexes them.

Googlebot - The generic name of Google's crawler. Googlebot crawls the web constantly.

SEO - Search engine optimization: the process of making your site better for search engines. Also the job title of a person who does this for a living: We just hired a new SEO to improve our presence on the web.

Total Clicks - Total number of times a user clicked through to your site. How this is counted depends on the search result type.

Total Impressions - Total number of times a user saw a link to your site in search results. This is calculated differently for images and other search result types, depending on whether the result was scrolled into view.

Average CTR - It is the percentage of impressions that resulted in a click.

Average Position - It is the average position in search results for your site, using the highest position for your site whenever it appeared in search results.

Content Courtesy: Google Search Central