From Wiktionary, the free dictionary
From J/C + -er.
J/Cer (uncountable)
- A fan who ships the Star Trek characters Kathryn Janeway and Chakotay.
1996 September 19, CWilson980, “Voy Alternate Basics J/C pt 1”, in alt.startrek.creative[1] (Usenet):They are both in a script-like style I am a committed J/Cer, so I do include romantic developments.
1998 April 12, Di, “Help finding a Story”, in alt.startrek.creative[2] (Usenet):The story I'm referring to was identified as a vignette and it was very sad, well at least it was sad for a J/Cer such as I.
2001 March 23, Kattz, “VOY Feedback Vote #3 by CyberMum”, in alt.startrek.creative[3] (Usenet):A lovely 'what if' that all ardent J/Cers would love to see.