In Apple's Macintosh operating systems, labels are a type of seven distinct colored and named parameters of metadata that can be attributed to items (files, folders and disks) in the filesystem.
[1] Labels were introduced in Macintosh System 7, released in 1991,[2] and they were an improvement of the ability to colorize items in earlier versions of the Finder.
[5] During the short time period when Mac OS X lacked labels, third-party software replicated the feature.
[6][7] In classic Mac OS versions 7 through 9, applying a label to an item causes the item's icon to be tinted in that color when using a color computer monitor (as opposed to the black-and-white monitors of early Macs), and labels can be used as a search and sorting criterion.
[5] The Mac operating system has allowed users to assign multiple arbitrary tags as extended file attributes to any item ever since OS X 10.9 was released in 2013.