Con may refer to any of the following:
1. Con is an MS-DOS and Microsoft Windows reserved word.
2. When referring to games con is short for consider and is an ability or command used to find out additional information about the targeted creature or player. For example, in the MMORPG game EverQuest a player can type: /con to find out additional information about the target.
3. Con is another term used to describe a deception or trick. For example, phishing is a con that often deceives the user to give away their log in information.
4. A con is any negative feedback or lack of features of a product. For example, the pro's and con's of Linux vs. Windows.
5. Short for conference, con is used as an abbreviation when describing a conference or other get together. For example, DEF CON is an example of where this term is used.