What is spid?

I ran sp_who2 in sql server, what is SPID?
From Microsoft, I found that it is session ID.(I copied it at bottom).
I used ASP.NET in app, what is the relationship between SPID and connection string? Is it processing ID?
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session ID (SPID in SQL Server 2000 and earlier) is a session identification number belonging to the SQL Server instance. session ID is smallint.

the spid uniquely idendifies a given connection to the database. the relationship is that you connect, you get a spid. the connectionstring doesn't affect the spid and the spid does not affect the connectionstring. it is any connection to the server. If you make multiple connections to the server at the same time, you get multiple spids assigned. Also spid is what you pass to the sproc to kill a process (something that should only be done under extreme circumstances) on the server.

-tg

aspfun, was this just a general question, or are you having a specific issue that you are trying to fault find?

Gary