Reciprocal Links

When website A links to website B and B links back to A and both link to the other on condition that they receive a link back, this is reciprocal linking. The principle is that if site A ever removes the link to site B, site B will remove its link to site A and vice versa. This is a (not great) tactic for gaining more links pointing to a website in the hope that Google will increase the site’s ranking as a result