monolith

Concise Oxford English Dictionary © 2008 Oxford University Press:
monolith/ˈmɒnəlɪθ/

▶noun

• 1 a large single upright block of stone or concrete, especially a pillar or monument.

• 2 a large and indivisible organization or institution.

– origin C19: from Fr. monolithe, from Gk monolithos, from monos ‘single’ + lithos ‘stone’.