The Collaborative International Dictionary
Sororize
Sororize \So*ro"rize\ (? or ?), v. i. [L. soror, sororis, a sister.] To associate, or hold fellowship, as sisters; to have sisterly feelings; -- analogous to fraternize. [Recent & R.]
Wiktionary
sororize
vb. To associate, or hold fellowship, as sisters; to have sisterly feelings.