TITLE: Whence “homomorphism” and “homomorphic”?
QUESTION [33 upvotes]: Today homomorphism (resp. isomorphism) means what Jordan (1870) had called isomorphism (resp. holoedric isomorphism). How did the switch happen?
“Homomorphic” (and “homomorphism” as “property of being homomorphic”) are e.g. in de Séguier (1904, pp. 65–66) and the last edition of Weber (1912, p. 195). “Homomorphism” as map of groups is e.g. in Schur (1924, p. 192). But none of these sound like a first.
I asked this on hsm a week ago, but got no answer there.

REPLY [49 votes]: I found this footnote on page 195 of Fricke and Klein's Vorlesungen über die Theorie der automorphen Functionen (1897):

Translation:

The term "homomorphic" seems more appropriate than the previously$^\ast$ used "isomorphic", because it refers not to "equality" but to "similarity" of two groups. The term "isomorphism" will therefore from now on be used in the sense of "1-to-1 homomorphism".

$^*$l.c. = loco citato — this seems to refer to Fricke and Klein's Vorlesungen über die Theorie der elliptischen Modulfunctionen (1890).