.ADT file extension is commonly associated with files related to the Addict Dictionary, a dictionary and spell-checking software used in Borland Delphi and C++Builder development environments. The ADT file typically contains dictionary data that the Addict software uses for spell-checking in various applications.

How to Open ADT Files:

Opening ADT files typically requires the use of software that supports the Addict Dictionary file format. Here are some general steps:

1. Addict Dictionary Software:

2. Integrated Development Environments (IDEs):

Various Apps that Use ADT Files: