What is a “legacy application”?

Recently someone asked me how I defined something to be a “legacy application”. I didn’t have an immediate answer. With some Googling I found this really good definition from a Washington State Technology agency’s report.

To me, it also showed how sometimes we “know” things in our head but when asked have a tough time articulating it. Especially humbling when people think this is your area of expertise and expect you to rattle off an answer the moment they ask!

If you are curious, the source report is here:

https://watech.wa.gov/sites/default/files/2024-10/FY20-21BiennialReport%20FINAL.pdf