What's a "worker", or a "worker name"
In pool mining context a
workeris simply a machine that mines the blockchain.
A mining rig is a computer system used for mining bitcoins. The rig might be a dedicated miner where it was procured, built and operated specifically for mining or it could otherwise be a computer that fills other needs, such as performing as a gaming system, and is used to mine only on a part-time basis. wiki
Its a name to identify your machines when you connect it to a pool with a miner address. You can use the same mining address on different
rigs and identify them with
rigname, some pools show the rig name on the status page.