What does 1st, 2nd, & 3rd degree connection mean in LinkedIn profiles?

Your network is made up of your 1st-degree, 2nd-degree, 3rd-degree connections, and fellow members of your LinkedIn groups. 1st-degree - People you're directly connected to because you've accepted their invitation to connect, or they've accepted your invitation. ... You can contact them by sending a message on LinkedIn.

On LinkedIn, people in your network are called connections. Your network is made up of your 1st-degree, 2nd-degree, 3rd-degree connections, and fellow members of your LinkedIn groups.

1st-degree - People you're directly connected to because you've accepted their invitation to connect, or they've accepted your invitation. You'll see a 1st degree icon next to their name in search results and on their profile. You can contact them by sending a message on LinkedIn.

2nd-degree - People who are connected to your 1st-degree connections. You'll see a 2nd degree icon next to their name in search results and on their profile. You can send them an invitation by clicking Connect or contact them through an InMail. 

3rd-degree - People who are connected to your 2nd-degree connections. You'll see a 3rd degree icon next to their name in search results and on their profile.

• If their full first and last names are displayed, you can send them an invitation by clicking Connect.
• If only the first letter of their last name is displayed, clicking Connect isn't an option but you can contact them through an InMail.

Fellow members of your LinkedIn Groups - These people are considered part of your network because you're members of the same group. You'll see a Group icon next to their name in search results and on their profile. You can contact them by sending a message on LinkedIn or through the group.