Xilinx timing parameter definitions? e.g. Tbxcy, Tcinck, etc? Where are they defined?

Hi FPGA Folk, Is there any xilinx or other documentation that describes what these symbols mean? E.g. Tcko, Tbxcy, Tcinck?

The FPGA datasheets define a small subset of all the possible parameters defined in the speedfiles (accessible with speedprint). E.g. Tcko is the flop clock to out. Great. But what about Tbxcy and Tcinck? I can sortof guess what they might be, but surely these are defined somewhere?

(I'm using ISE 9.1 sp3 - clicking on the blue underlined hyperlinks in the timing report is only randomly successful. When the work they link to an html view of the logic cell, and highlight the primative that the symbol relates to.)

Cheers