Primary, secondary, and tertiary navigation.
Primary:
your main header nav, and this should be the big guns of your business, product, or service and what your customers will be looking for and will immediately find easily. Maybe a CTA button as well of which the purpose is what action you want your site visitor to take (alternately, you can place your CTA in the top bar/secondary nav). I try to keep the number of links in this section to 7 or less, and occasionally omit the HOME link if the target audience is savvy enough to know the logo/company name links to the home page. I also include the logo or entity name, with easy-to-understand tagline in this section.
Secondary:
a top bar with email, phone, maybe address (or map icon) if brick/mortar; sm links; and "secondary" links that are not as critical as links in your primary nav. You can also place your CTA button in this section rather than the primary nav.
Tertiary:
in the footer. Basically all nav links for easy access (perhaps separated into columns by content), along w/ contact/location info, SM links, logo/company name, and tagline.
Examples here and here of primary and secondary navigation.
Example here of primary, secondary, and tertiary navigation.