plank /plæŋk/ BrE AmE noun [countable]
[ Date: 1200-1300 ; Language: Old North French ; Origin: planke , from Latin planca , from plancus 'flat' ]
1 . a long narrow piece of wooden board, used especially for making structures to walk on:
a long plank of wood
a bridge made of planks
2 . one of the main features or principles of an argument etc ⇨ platform
plank of an argument/policy/campaign etc
the main plank of their argument
a central plank of our policy
a five-plank campaign including raising the minimum wage
⇨ walk the plank at ↑ walk 1 (13), ⇨ as thick as two short planks at ↑ thick 1 (7)