means A garden structure of upright posts supporting an open framework of crossbeams, often used to support climbing plants and create partial shade over a walkway or patio.

from From Italian pergola, descended from Latin pergula, meaning a projecting roof, balcony, or vine-trellis attached to a building. The Latin word likely traces back to pergere, 'to come forward' or 'project out' — fitting for a structure that reaches out from the house into the garden. It entered English in the 17th century, carried along with Italian gardening fashions.