Wikipedia
XBase
xBase is the generic term for all programming languages that derive from the original dBASE ( Ashton-Tate) programming language and database formats. These are sometimes informally known as dBASE "clones". While there was a non-commercial predecessor to the Ashton-Tate product (Vulcan written by Wayne Ratliff), most clones are based on Ashton-Tate's 1986 dBASE III+ release — scripts written in the dBASE III+ dialect are most likely to run on all the clones.