Mac OS X
Mac OS X 10.0 Cheetah (Mar 2001) - Introduced the new UNIX-based core and aqua visual interface, though it ran slow.
Mac OS X 10.1 Puma (Sep 2001) - Boosted overall system speed and added easy CD/DVD burning.
Mac OS X 10.2 Jaguar (Aug 2002) - Brought Finder search bars, QuickTime MPEG-4, and Universal Access.
Mac OS X 10.3 Panther (Oct 2003) - Made Safari the default web browser and introduced Font Book.
Mac OS X 10.4 Tiger (Apr 2005) - Added Spotlight search, Dashboard widgets, and initial Intel chip support.
Mac OS X 10.5 Leopard (Oct 2007) - Added Time Machine backups, Spaces, and Boot Camp.
Mac OS X 10.6 Snow Leopard (Aug 2009) - Cleaned up old code for efficiency and launched the Mac App Store.
Mac OS X 10.7 Lion (Jul 2011) - Brought iPad elements like Launchpad and full-screen apps.
OS X
OS X 10.8 Mountain Lion (Jul 2012) - Integrated iOS features like Notes, Messages, and Notification Center.
OS X 10.9 Mavericks (Oct 2013) - Brought tabbed Finder, iCloud Keychain, and free yearly updates.
OS X 10.10 Yosemite (Oct 2014) - Shifted to a flat, translucent design and Continuity features.
OS X 10.11 El Capitan (Sep 2015) - Improved split-view window management and overall system performance.
macOS
macOS 10.12 Sierra (Sep 2016) - Renamed the OS to macOS and brought Siri to the desktop.
macOS 10.13 High Sierra (Sep 2017) - Upgraded the core data file system to APFS.
macOS 10.14 Mojave (Sep 2018) - Introduced a system-wide Dark Mode and dynamic desktop backgrounds.
macOS 10.15 Catalina (Oct 2019) - Dropped 32-bit app support and split iTunes into separate media apps.
macOS 11 Big Sur (Nov 2020) - Redesigned the interface to match iOS and added native M1 Apple Silicon support.
macOS 12 Monterey (Oct 2021) - Introduced Universal Control and SharePlay capabilities.
macOS 13 Ventura (Oct 2022) - Added Stage Manager for window control and Continuity Camera.
macOS 14 Sonoma (Sep 2023) - Brought interactive desktop widgets and game-mode enhancements.
macOS 15 Sequoia (Sep 16, 2024) - Introduced Apple Intelligence AI tools, iPhone Mirroring, and native window tiling.
macOS 26 Tahoe (Sep 2025) - Introduced a new interface language, deep system intelligence, and major application updates.
macOS 27 Golden Gate (Fall 2026) - Siri AI, next-generation Apple Intelligence, and refining the previous "Liquid Glass" design language
**** First version to run exclusively on Apple Silicon - no Intel support ****