Refers to the craft or business of upholstery.
La empoltronecería de ese sofá es tan cómoda que me quedaría dormido.
The upholstery of that sofa is so comfortable that I would fall asleep.
La empoltronecería del sofá estaba desgastada, por lo que decidimos renovarla.
The upholstery of the sofa was worn out, so we decided to renew it.