Big O and Big Omega denotes Worst Case and Best case Respectively. Is it True?

I am just searching on google about Difference between Big Oh, Big Omega and Big Theta and found the first google search the geeksforgeeks article which says Big oh (O) – Worst case, Big Omega (Ω) – Best case and Big Theta (Θ) – Average case. Is this right?

https://www.geeksforgeeks.org/difference-between-big-oh-big-omega-and-big-theta/#:~:text=Big%2DO%20is%20a%20measure,Big%2DO%20and%20Big%2D%3F