is a specific kind of: size.

is a broader term that covers: ampleness | bulkiness, massiveness | enormousness, grandness, greatness, immenseness, immensity, sizeableness, vastness, wideness | capaciousness, commodiousness, roominess, spaciousness | fullness, voluminosity, voluminousness | giantism, gigantism.

is the opposite of: littleness, smallness.

derivation: big, enceinte, expectant, gravid, great, heavy, large, with child | big, large.