tantity

ˈtantity nonce-wd.,

a rendering of mod.L. tantitās, ‘the fact of being or having so much’, f. L. tāntus so much.

[Attributed in some recent dictionaries (from Annandale's Ogilvie, 1882, onward) to James Mill, who used only the Latin (Elem. Human Mind, 1829, II. xiv. §2, 50) ‘Quantitas, if it was kept to its original meaning, would still connote tantitas; just as paternity connotes filiality’.]