Original text:
The transport protocol described by this document.  QUIC is a name, not an acronym. <del> A complete processable unit of QUIC that can be encapsulated in a UDP datagram.  Multiple QUIC packets can be encapsulated in a single UDP datagram. A QUIC packet that contains frames other than ACK, PADDING, and CONNECTION_CLOSE.  These cause a recipient to send an acknowledgment; see sending-acknowledgements. </del> An entity that can participate in a QUIC connection by generating, receiving, and processing QUIC packets.  There are only two types of endpoint in QUIC: client and server. The endpoint that accepts a QUIC connection.  When used without qualification, the tuple of IP version, IP address, and UDP port number that represents one end of a network path.

Reviewer comments:
I struggled with this a little. Happy to take suggestions.
I'm going to say that the IP Packet vs. QUIC Packet text is not necessary. We carefully qualify where there is any potential for confusion.
On the other issue, it might be worth simply stating the terminology upfront. Something like


Datagram Size There is some confusion in the text between packets, frames and datagrams. That could be helped by earlier clarification.
This is a duplicate of .
12.4. Frames and Frame Types Packet Payload { Frame (8..) ..., } Version Negotiation, Stateless Reset, and Retry packets do not contain frames. At this point (page 82) I am still not sure what a packet or a frame is and have no idea what is going on on the wire.
Probably a duplicate of . These terms should be added to the definitions, with possibly some additional explanatory text in Section 12.
Section 1 is the first place that you introduce the term "Frame". I got very confused about frames and packets, and I thing the taxonomy needs to be clearly explained. You have UDP/IP packets that carry one or more QUIC PDUs, but the frame/packet notation made it unclear what was being discussed and whether the terms were being used consistently. Some clarification would be useful, or if it is in the text then making it more obvious would help.
Perhaps "frame" and "datagram" should be added as defined terms in Section 1.2. On a related note, the defined term is "QUIC packet" but in the text we don't always specify what type of "packet." Perhaps we should define "packet" as generally referring to QUIC, with a note that IP packets will be indicated as such. (I believe all instances of "packet" that refer to IP explicitly say "IP packet," but we should verify that.)
One small suggestion, which you can ignore if you don't like it.

Revised text:
The transport protocol described by this document.  QUIC is a name, not an acronym.  An entity that can participate in a QUIC connection by generating, receiving, and processing QUIC packets.  There are only two types of endpoint in QUIC: client and server. The endpoint that accepts a QUIC connection. <ins> A complete processable unit of QUIC that can be encapsulated in a UDP datagram.  One or more QUIC packets can be encapsulated in a single UDP datagram. A QUIC packet that contains frames other than ACK, PADDING, and CONNECTION_CLOSE.  These cause a recipient to send an acknowledgment; see sending-acknowledgements. A unit of structured protocol information.  There are multiple frame types, each of which carries different information.  Frames are contained in QUIC packets. </ins> When used without qualification, the tuple of IP version, IP address, and UDP port number that represents one end of a network path.