Software tool
Software tools are usually thought of as programs that software developers use to create other programs.
The history of tools really begins long ago, but became famous with Unix. Unix tools like grep, awk, and make where meant to be combined flexibly with pipes.
Tools were originally simple and light weight. As some tools have been maintained, they have been integrated into more powerful IDEs or integrated development environments. These environments usually make searching and editing much easier, however they lack the ability to massage code, like old Unix tools.
The distinction between tools and applications is quite murky. For example, developers use simple databases (for example a file containing list of important values) all the time as tools. However a full blown database is usually thought of as much more than a tool.
Software tools come in many forms:
Source Code Control
Something
Search
Scripts
Parsing
Bug Databases