SSD Solid State Drive
Modern storage with no moving parts — flash memory instead of spinning platters.
Many times faster than mechanical hard drives (HDD): ~5-second boot instead of 60, app launch in a beat instead of with a waiting sound. Doesn't handle infinite write cycles but typical lifespan is 5+ years.
NVMe SSDs are even faster than regular SATA SSDs. Standard in new laptops since ~2018.