An interactive timeline of the most iconic infographics

I guess the missing word is "curve?" I find that a little hard to believe; surely continuous curves were drawn much, much earlier, way before the terminology of continuity was available—for example, in the work of Euclid. Even if we ask that they be thought of as curves in the modern-day calculus-class sense of the word, surely Descartes's and Fermat's work counts as such.

Maybe you're just relaying information from the meta-infographic, though I can't find it (I find it charming but difficult to navigate); all I see is "1686: Empirical Observations."

(For that matter, the formal terminology of continuity as we learn it in calculus today had to wait until Cauchy and Weierstrass in the 19th century.)