# ATTDEF Command [GstarCAD 2027](Help%20System/GSTARCAD/2027/Index.md) → [Commands](Help%20System/GSTARCAD/2027/Commands/(Commands).md) **Function Description:** This command is used to create an attribute definition for storing data in a block. The [Attribute Definition dialog box](Help%20System/GSTARCAD/2027/Commands/03%20Dialog%20Boxes/Attribute%20Definition%20Dialog%20Box.md) is displayed. **Command Access:** > **Icon:** ![](Help%20System/GSTARCAD/2027/assets/f4a2477112f426dcaf947fc79fdecfbb99ce0c8168aef8f0e0219215a7e0dfbb.png) > **Menu:** Draw > Block > Define Attributes > **Ribbon:** Insert > Block Definition > Define Attribute > **Toolbar:** BE: Manage > Define Attribute > **Command:** ATTDEF > **Alias:** ATT **Command Prompts: /** --- **Related References：** - [Commands about Block Attributes (GstarCAD 2026)](../../2026/Commands/00%20Command%20Groups/Commands%20about%20Block%20Attributes.md) **Related Concepts：** - [About Defining and Attaching Block Attributes (GstarCAD 2026)](../../2026/Commands/02%20Concepts/About%20Defining%20and%20Attaching%20Block%20Attributes.md) **Related Tasks：** - [To Create and Attach an Attribute Definition (GstarCAD 2026)](../../2026/Commands/01%20Procedures/To%20Create%20and%20Attach%20an%20Attribute%20Definition.md) --- [Original help](https://www.gstarcad.net/help/GstarCAD_2027_en-US/detail/commandReferences/ATTDEF.html) · © Gstarsoft Co., Ltd.