footing

anchorage, bed, brace, bulwark, buttress, framework, infrastructure, mount, prop, shore, stay, substratum, substructure, support

assumption, justification, premise (also premiss), presumption, presupposition, rationale, supposition, theory, thesis, warrant

backbone, center, core, cornerstone, eye, focus, heart, hub, kernel, keystone, nucleus, seat

essence, quintessence, soul, touchstone

rank, standing

place, spot, state

score, status quo

condition, estate, order, walk

capacity, function

rating