I'm not aware of any bond symbols - since bonds don't trade on a centralised exchange, I don't believe they have universal symbols attached to them like stocks do.
About the nearest thing I can think of is CUSIP numbers - you can find CUSIP from corporate issuers somewhere like investinginbonds.com:
http://www.investinginbonds.com/mark...e.asp?catid=34
Aside from that, the only other option that comes to mind is that it may have been unique to your data service provider or a dealer convention, as data providers will assign some kind of symbol or other short cut to at least some of the bonds to help identify them more quickly.
But in such a case, the provider symbols will differ depending on the provider, just like the symbols used to identify various averages and indexes, i.e., Reuters identifies the NASDAQ composite as ^IXIC while Bridge uses something like COMPX, etc.
Hope that helps, and welcome to FM, Bob.