Windows: Visual Basic controls (need VBRUN100.dll).
Visual Basic Extension. Custom controls originally designed for 16-bit applications created by Visual Basic. Visual Basic version 4.0 introduced the ActiveX Control (OCX) model as its main control architecture in order to support controls in both 16-bit and 32-bit environments.
The file extension (and generic name) of components used by 16-bit versions of Visual Basic (VB1 through VB4). Now obsolete, VBXs do not have two of the properties (inheritance and polymorphism) many believe are required by true object-oriented systems. Starting with VB5, OCX and then ActiveX controls became current.