ETA
ETA has 2 meanings
Edited to add
In forum posts, ETA typically stands for "edited to add." This acronym signals that a user has edited their original post to include some additional context or other extra information.
Most often, you'll see "ETA:" appended to the end of posts or comments, alongside whatever information a user added. For example, a Reddit comment about how best to wash your clothes might end with "ETA: Washing on cold is best for the environment and decreases your heating bill. Use your washer's cold setting!" In this case, the Redditor added the information about cold washing to their initial comment.
Example
Anyone who says you can't replace your own toilet shut-off valve is just trying to milk you for some money. ETA: For context, I'm a lifelong home repair contractor. So I know what I'm talking about here
How well do you know your Fantasy Football slang?
ETA is a common way to refer to the estimated time a person, package, airplane, etc., is expected to arrive. Most people use it to let others know when they plan to reach a destination, whether for a movie, dinner, vacation, etc.
You may see ETA in various contexts, including emails, messages, printed tickets, and in person (verbally). For example, you may email your family, "My ETA for Thanksgiving dinner is 3 pm." Or, you might text your friend, "Sorry we are running late. Our ETA is about 20 minutes. You can start without us!"