Someone explain Server Tickrate's to a n00b

[CCP115]

I have the jist of client network settings and all that stuff, mainly for TF2, as I play it the most, and I know the server tickrate is defaulted to 66.

What is the tickrate? In simple terms, what is it? Does it affect some client network settings like cl_interp and all that?
Does it affect lerp timing, or is that based on a separate value?
What do these commands do, sv_minrate, sv_minupdaterate, and sv_mincmdrate? (and max all of those as well, sv_maxrate, etc.)

 

[Vegeta897]

I dunno the answers to your other questions but tickrate is how many times per second the server simulates 1 step of the game.

You seem to know what lerping is, so maybe you already knew that and you're asking something else.

 

[CCP115]

Does tickrate affect the number of updates the server sends to you, which in turn affects lerp?

The Source Dev Wiki said it was 20 snapshots per second, but is that related to tickrate in anyway?

 

[Vegeta897]

That I do not know, sorry.