Started when a moth was found between two relays inside a government(US) computer back when a computer occupied an entire room/storage center.
Flash back to the new century and a bug refers to a glitch which causes a computer program or hardware to malfunction, resulting in unwanted actions. These actions can range from a program failing also refered to as BSoD, or a CTD. If hardware is affected, the results can mean lower performance, or inability to boot.
A bug can be remedied in a number of ways, an update from the hardware manufacturer, an update from the software vendor, or help from a tech savvy community. The latter of the three usually doesn't include a permanent fix, but a loop around the problem resulting in desired performance without the intervention of the manufacturers.
Can be used to describe a large variety of sexually transmitted deseases but this term is most well known for meaning THE BIG ONE... HIV or AIDS.
Jason bugs...he stood me up for dinner last night!