buttress

noun

1. A brick, concrete or stone structure built against another structure to support it.

   “It was decided, therefore, to build eight concrete buttresses from the new strengthening work to safeguard the general stability of the wall along the length where the greatest movement had taken place.”

2. (broadly)Anything that serves to support something; a prop.
3. A buttress root.
4. A feature jutting prominently out from a mountain or rock.

   “Crowell Buttresses, Dismal Buttress”

   “All that day they rode into broken land. The prairie with its grass and rolling hills was behind them, and they entered a sparse, dry, rocky country, full of draws and short cañons and ominous buttresses.”

   “Two short pitches up a chimney-crack are followed by a traverse right to the centre of the buttress.”

5. (figuratively)Anything that supports or strengthens.

   “the grand pillar and buttress of the good old cause of nonconformity”

verb

1. To support something physically with, or as if with, a prop or buttress.
2. (broadly, figuratively)To support something or someone by supplying evidence.

   “Buttressed by elaborate account statements and a deep reservoir of trust from his investors and regulators, Mr. Madoff steered his fraud scheme safely through a severe recession in the early 1990s, a global financial crisis in 1998 and the anxious aftermath of the terrorist attacks in September 2001.”