Basically its stands for segregated witness.

Its a kind of update to the bitcoin protocol. Basically we're making more space in each block of the btc blockchain so that more transactions can be processed in a block.

If you noticed while bitcoin was at its peak a month or so ago, transactions were becoming slow to confirm and the transaction fees were becoming large.
Segwit basically solves this(to some extent) and makes bitcoin more scalable.


I could go more technical if you want more info.

Also most of the nodes are running segwit so it is very likely that it will activate by Aug 1st(thats the proposed deadling).


And we will see a large bull run in the market if everything goes well.