A unexplainable technical outage that causes end-users to despise network administrators. Typically, the term "hiccup" is used either:
to "dumb down" the explanation for the less-technically-inclined
because the network administrator hasn't a clue about what has happened and doesn't want anyone to know he can't explain the problem.
The reason you couldn't login to your computer this morning was due to a "technical hiccup" and has thus been fully digested. Thank you for your patience and have a nice day.