1) Architectural element 
In architecture, a hypostyle (-) hall has a roof which is supported by columns, as in the Great Hypostyle Hall at Karnak. The word hypostyle comes from the Ancient Greek ὑπόστυλος hypóstȳlos meaning `under columns` (where ὑπό hypó means below or underneath and στῦλος stŷlos means column). The roof may be constructed of w.....
pillar
• (a.) Resting upon columns; constructed by means of columns; -- especially applied to the great hall at Karnak.
Hy'po·style adjective [ Greek ... resting on pillars; ... under + ... a pillar.] (Architecture) Resting upon columns; constructed by means of columns; -- especially applied to the great hall at Karnak. 
In architecture the term hypostyle is applied to something resting upon columns or constructed by means of columns. The term is especially applied to the great hall at Karnak.
(Greek hupostulos, under columns) Building with roof supported by pillars