DNS Lookup is the time required to resolve a host name (e.g. www.google.com) into a numeric IP address (e.g. 126.96.36.199).
Connect is the time required to create a TCP connection to the web server (or proxy). If a secure HTTPS connection is being used this time includes the SSL handshake process. Keep-Alive connections are often used to avoid the overhead of repeatedly connecting to the web server.
Send is the time required to send the HTTP request message to the server and will depend on the amount of data that is sent to the server. For example, long Send times will result from uploading files using an HTTP POST.
Wait is the idle time spent waiting for a response message from the server. This value includes delays introduced due to network latency and the time required to process the request on the web server.
Receive is the time taken to read the response message from the server. This value will be depend on the size of the content returned, network bandwidth and whether HTTP compression was used.