Meaning of PLANK in English

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)

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.