Half a nanosecond. The onosecond is that split second when one realizes that a faux pas or a terrible mistake has been made. Same as an ohnosecond. It took Sandy only an onosecond to realize that she should not have asked Rusty who the father of the child was.
ohnosecond
That moment just after you realise you have made a big mistake. Same as an onosecond. Tom paused for an ohnosecond then climbed out to see who he had backed into.
ohnosecond
<unit, humour> (Presumably a play on "nanosecond") The
miniscule time it takes to realize that you've just made a BIG
mistake like typing rm -rf * in the wrong directory.
Seen in Elizabeth P. Crowe's book, "The Electronic Traveller."
(1998-08-27)