A hot fix is a single, cumulative package that includes one 
or more files that are used to address a problem in a 
software product. Typically, hotfixes are made to address a 
specific customer situation and may not be distributed 
outside the customer organization.

Bug found at the customer place which has high priority.

Hotfix is a serious bug which found in the prodution level 
which needs to be fix immediatly.

Hi,

   Hot fix is show stopper.. that bug has to be immediately.

Regards,
Satya.k

A hotfix is code (sometimes called a patch) that fixes a 
bug in a product. Users of the products may be notified by 
e-mail or obtain information about current hotfixes at a 
software vendor's Web site and download the hotfixes they 
wish to apply. Hotfixes are sometimes packaged as a set of 
fixes called a combined hotfix or a service pack.

A hotfix is a software package that are used to solve a 
particular problem/bug. One hotfix may be used to address 
more than 1 bug. They are similar to patches. This is more 
helpful in regression process because they are prepared in 
keeping possible side effects into consideration.

Cheerz,
Saurabh garg