Basic definition encompassing many tools which can be used to inflict damage or harm upon the object of it's blows.
In human usage, they are constructed mainly for solving disputes related to sex or money, or, in some cases, both.
A better alternative to weaponry is to simply become massively proficient in perl and code a sentient being to "off" the person worthy of revenge. In this way, you get much more credit from the geek community.