hardpan

• POS: Noun
• HYPHEN: hard=pan

CIDE DICTIONARY

hardpan, n. 

 The hard substratum. Same as Hard pan, under Hard, a.  [1913 Webster]

OXFORD DICTIONARY

hardpan, n. Geol. a hardened layer of clay occurring in or below the soil profile.

ROGET THESAURUS

hardpan

Base

N base, basement, plinth, dado, wainscot, baseboard, mopboard, bedrock, hardpan, foundation, substructure, substratum, ground, earth, pavement, floor, paving, flag, carped, ground floor, deck, footing, ground work, basis, hold, bilge, bottom, nadir, foot, sole, toe, hoof, keel, root, centerboard, bottom, undermost, nethermost, fundamental, founded on, based on, grounded on, built on.