What is the Full Form of VHDL ?

VHDL - VHSIC Hardware Description Language

Here, VHSIC stands for Very High Speed Integrated Circuit

VHSIC Hardware Description Language is a hardware description language used to describe a logic circuit by function, data flow behaviour, or structure. It can also be used as a general purpose parallel programming language i.e. commands, which correspond to logic gates, are executed (computed) in parallel, as soon as a new input arrives.

Like a program written in any language, can be executed, a program written in VHDL can be executed. But, since the language is used to model designs, it is always pronounced as simulated instead of getting executed.