Definition of "quantic"

When the two quantics are the first derived functions of the same quantic of any odd order, the lineo-linear invariant does not vanish, but it is not an invariant of the single quantic.

1858, Arthur Cayley, “A Fourth Memoir on Quantics”, in Philosophical Transactions of the Royal Society of London, volume 148, published 1859, page 421

74. The discriminant of a binary quantic, or the eliminant of a system of binary quantics, is an invariant.We can see a priori that this must be the case, for if a given quantic has a square factor, it will have a square factor still when it is linearly transformed; or if a system of quantics have a common factor, they will still have a common factor when the equations are transformed.

1859, George Salmon, Modern Higher Algebra, page 52