A Quick and Simple Dictionary

Schwarzian

1. Noun.  (singulare tantum) A particular operator that, when applied to a function (f) yields a function $xmapstofrac\{f\text{'}\text{'}\text{'}(x)\}\{f\text{'}(x)\}-frac32left(frac\{f\text{'}\text{'}(x)\}\{f\text{'}(x)\}\; ight)^2$.
2. Noun.  (countable) Any image of that operator.