“Conlang” is short for “constructed language”. All fictional languages, from Elvish to Dothraki via Klingon, are conlangs.
A while ago, I came up with my own. It serves as extremely useful shorthand when I don’t want anybody peeking over my shoulder (though, I’ll be honest, I don’t always remember all of the letters… there are 22 vowels and 13 consonants, because I’m ambitious like that. I generally forgive myself the mistakes, though).
I have a blog post or two about conlanging planned for the future, but now, it is late, I have had a lovely evening of food and wine and I think it’s time for bed!