As nouns the difference between cullin and cullion
is that cullin is any of a family of proteins that have a role in protein degradation and ubiquitinylation while cullion is testicle.
cullin
English
Noun
(
wikipedia cullin)
(
en noun)
(protein) Any of a family of proteins that have a role in protein degradation and ubiquitinylation
----
cullion
English
Noun
(
en noun)
Testicle.
A vile person.
References
* Holinshed's Chronicles