QUIC stands for “Quick UDP Internet Connections” and is, itself, Google’s attempt at rewriting the TCP protocol as an improved technology that combines HTTP/2, TCP, UDP, and TLS (for encryption), among many other things.

Source: HTTP-over-QUIC to be renamed HTTP/3 | ZDNet

Since then, HTTP-over-QUIC support was added inside Chrome 29 and Opera 16, but also in LiteSpeed web servers. While initially, only Google’s servers supported HTTP-over-QUIC connections, this year, Facebook also started adopting the technology.