Here’s a nice summary from Wikipedia; it’s a defensive tactic, devised by Lt (later Adm) Jim Thach. Highly successful in negating some of the speed and maneuverability advantages of the Japanese Zero.
Thach was a brilliant tactician. But perhaps he deserves most credit for believing the fleet intel report (issued in September 1941) that reported the Zero was much faster and far more maneuverable that U.S. fighters like the F4F Wildcat and the P-40 Warhawk.
Much of that information came from Claire Chennault’s Flying Tigers, who had been battling Japanese Zeros for many months and learned they could not survive a turning fight with the enemy fighter. Many Army Air Corps pilots had access to the same info and dismissed it; there was no way the Japanese could produce fighter aircraft and pilots superior to our own. A lot of those pilots paid for that assumption with their lives.
Here’s a description of the Thach weave: https://en.wikipedia.org/wiki/Thach_Weave
Oh cool, they ran a pick on them. :)