Also, out of date can mean expired...as in my passport is out of date so I need to get it renewed

I agree with these other responses ! obsolete- no longer used out of date- old fashioned or used with rotten food outdated- meaning something is no longer trendy anymore dated- meaning you can pinpoint what time its from.

The differences are subtle. Obsolete: Not in use anymore, something that has been definitely replaced by something newer or better. Outdated/out of date: Old fashioned and not as good as something modern. Dated: something with a very obvious origin in a bygone time. Depending on context, they all can be used in place of each other.

Obsolete - now useless...CDs made cassettes obsolete...now mp3s have made CDs obsolete. Food can be out of date if it's too old/going bad. Outdated kinda means old and problematic...laws for regulating newspapers are outdated now we have the internet. As science and technology improve, old ideas become outdated. Dated means you can identify the date something is from... archaeologists have dated the bones to 3 million years ago. Also think bad CGI in films (the Scorpion king) it looks very dated...you know it's from the 90s just by watching it