Segregated Witness for short: Segwit, first proposed by Bitcoin core developer Pieter Wuille in 2015. It is currently Bitcoin's better solution to deal with the expansion of capacity. Segregated Witness supports wallets with addresses that start with the number "3", in line with multi-signature wallets.

Benefits of Segwit:

1. Better security.
2. Can increase block capacity.
3. Faster checking of transactions.
4. Transaction fees will be cheaper than normal address types (addresses starting with 1).