ob- prefix

denoting 'obligatory or expected reference to' a topic


SF Fandom

  • [1951 E. F. Russell …And Then There Were None in Astounding Science-Fiction June 29/2 page image Eric Frank Russell bibliography

    Now…you've done something for me. That means you've planted an ob on me. I don’t thank you for what you've done. There’s no need to. All I have to do is get rid of the ob.]

  • 1993 E. S. Raymond New Hacker's Dictionary (ed. 2) 306

    Ob-, obligatory. A piece of netiquette acknowledging that the author has been straying from the newsgroup’s charter topic. For example, if a posting in alt.sex is a response to a part of someone else’s posting that has nothing particularly to do with sex, the author may append ‘ObSex’™ (or ‘Obsex’) and toss off a question or vignette about some unusual erotic act.

  • 2001 D. Crystal Language & Internet v. 146

    In Usenet, for example, there is the convention ob-[= obligatory] placed in front of a word to show that an attempt is being made to bring a topic back to the point, after it has gone off in various directions (e.g. obpassports was used after a discussion about passports had got sidetracked into one on holidays).

Research requirements

antedating 1991

Research History
Tom Whitmore submitted a 1951 cite from Eric Frank Russell's ". . . And Then There Were None", which is probably the first usage.
Garrett Wollman submitted a 1991 cite from Steele's and Raymond's "New Hacker's Dictionary".
Bill Mullins submitted a 1954 cite from the fanzine Confusion #16.

We would like any further cites of this usage (as "obligation"), but are primarily interested in cites of its use as a prefix, meaning "obligatory".

Last modified 2020-12-20 18:37:51
In the compilation of some entries, HDSF has drawn extensively on corresponding entries in OED.