A glider is a special type of armchair or sofa that glides back and forth in a smooth motion, similar to a rocking chair but in a horizontal motion instead of rocking in an arc.
A recliner is a chair that can be adjusted to lay flat or at an angle, but it doesn’t always move like a rocker or glider.
Some recliners have functions that allow them to rock, swivel or glide, and a glider may come with a reclining function, so they can sometimes be multifunctional and interchangeable.