I think the correct term would be navigation bar. While the navigation bar lets users access the main pages in the web site, the table of contents lets users access the exact content they want. Having a website that is easy to navigate and user friendly is very important to entice the viewers. Navigation bars are very important for easy access of the viewers to different parts of the website. Also, having a table of contents would be recommendable as it would allow viewers to scan certain parts. These two would go hand in hand in order to give viewers ease in scanning your website.