A sitemap shows google spiders to index your website.

site map is a list of pages of a website

A sitemap is a file where you can list the web pages of your site to tell Google and other search engines about the organization of your site content. Search engine web crawlers like Googlebot read this file to more intelligently crawl your site.

sitemap is a full list of urls on your website for webmasters
that they can easily grab your website

The sitemaps protocol allows a webmaster to inform search engines about urls on the website that are available for crawling.

Sitemap
 

Sitemap is the map of your site that submits in webmaster tool

Site map is a file which describes about the list of urls of your websites.

A sitemap informs search engines that individual pages on your site which allow in search engine.

A site map (or sitemap) is a list of pages of a web site accessible to crawlers or users. It can be either a document in any form used as a planning tool for Web design, or a Web page that lists the pages on a Web site, typically organized in hierarchical fashion.