a horizontal trellis or framework, supported on posts, that carries climbing plants and may form a covered walk
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
A garden structure consisting of an open wooden-framed roof, often latticed and supported by regularly spaced posts or columns and often covered by climbing plants to shade a walk or passageway.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
an arbor or a lightly trellised passageway of arches or pillars. Pergolas provide shelter from the heat. In 16th-century terraced gardens that were almost devoid of shade and in the 17th- and 18th-century formal parks, pergolas were three-dimensional accents against a background of plants pruned to appear as wall-like espaliers. They are used today in parks.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
1. A garden structure with an open wooden-framed roof, often latticed, supported by regularly spaced posts or columns. The structure, often covered by climbing plants such as vines or roses, shades a walk or passageway.
2. A colonnade which has such a structure.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.