Segregated Witness (SegWit)
The term “Segregated Witness” (SegWit) describes a modification to the Bitcoin transaction format. By raising block capacity, it was intended as a protocol improvement to protect against transaction malleability and shorten transaction times. Transaction malleability is the potential for minute details of transactions to be altered, invalidating fresh bitcoin blocks.
Additionally, by keeping more transactions in a block, the validation process was supposed to go more quickly.