F1 and F2 What douse it mean

I was just wondering what it means when you see F1 and F2 strain on the seed buying websites ?
Thanks for your input

it refers to how many times it was crossed. F1 will give you the least amount of phenotypes and is generally known as more stable

ah kk I get it so an F1 is more likely to be like its mother than to have its own attributes

https://www.rollitup.org/breeders-paradise/395655-creating-true-breeding-strains-vic.html
there is a link to this explained in great detail.

f1 is not to stable either is f2 i think f3 is semi stable but thats what ive read im not 100% positive.