However, we soon started realizing that the Finder backend would be useful outside of the Finder. Therefore, a plan was hatched to someday make it available as a public API. Since I had previously been responsible for naming Icon Services and Navigation Services, we decided to go with Desktop Services (at the time, we were also considering renaming the Finder to “Desktop”). Hence the name of the .DS_Store, for “Desktop Services Store”. We added a “.” in front of it so that it would be considered as an invisible file by Unix OS, including Mac OS.

Source: On the origins of DS_store