Payload is the amount of weight a robot can carry, lift, or manipulate. It sounds simple, but spec sheets often hide the hard part: payload depends on where the weight is, how long the robot must hold it, and whether the robot is standing still or moving.
A five-kilogram payload held close to the torso is not the same as a five-kilogram payload held at full arm extension. The second case creates more torque at the shoulder, elbow, wrist, hips, knees, and ankles. For humanoids, the whole body is part of the lift.
There are usually two useful payload questions. First: what can each hand or arm handle? Second: what can the whole robot move through the environment without becoming unstable or unsafe? Warehouse and factory use cases care about both.
When a company publishes a payload number, look for the test condition. Is it per arm or total? Static hold or repeated motion? A small box or an awkward object? If those details are missing, treat the number as a clue, not a capability claim.