A multi-link suspension is a type of vehicle suspension

Suspension (vehicle)

Suspension is the term given to the system of springs, shock absorbers and linkages that connects a vehicle to its wheels. Suspension systems serve a dual purpose — contributing to the car's roadholding/handling and braking for good active safety and driving pleasure, and keeping vehicle occupants...

 design typically used in independent suspension

Independent suspension

Independent suspension is a broad term for any automobile suspension system that allows each wheel on the same axle to move vertically independently of each other. This is contrasted with a beam axle, live axle or deDion axle system in which the wheels are linked – movement on one side affects...

s, using three or more lateral arms, and one or more longitudinal arms.
A wider definition considers any independent suspensions having 3 control arms or more multi-link suspensions.

These arms do not have to be of equal length, and may be angled away from their 'obvious' direction.

Typically each arm has a spherical joint (ball joint) or rubber bushing at each end.