The Collaborative International Dictionary
Anallagmatic
Anallagmatic \An`al*lag*mat"ic\, a. [Gr. ?; 'an priv. + ? a change.] (Math.) Not changed in form by inversion.
Anallagmatic curves, a class of curves of the fourth degree which have certain peculiar relations to circles; -- sometimes called bicircular quartics.
Anallagmatic surfaces, a certain class of surfaces of the fourth degree.
Wiktionary
anallagmatic
a. (context mathematics English) Not changed in form by inversion.