I would like to download an English lexicon (dictionary) - preferably a free one. I have searched online and all I can find is software.
I am looking to experiment with making software to create and solve puzzles.
Does anyone know where I can find such a thing.
Indeed there is such a thing. If you're familar with MySql database take a look here: MySQL English Dictionary - A Full English - English dictionary in MySQL Format
Yet Another Word List (YAWL) is primarily a quite large word list. It could be relevant for you. The repository contains utilities for anagrams, and the readme states it is quite usable for making word games.
