As was mentioned, Ruby has lambdas, but they are commonly called "procs".
This rhymes with "blocks" for a reason.

A block is really just syntax sugar for defining a proc and passing it into
a function.  Ruby allows for one block to be passed in to each method
(though you can, of course, pass as many procs as you want in the parameter
list).  It's a convenience, nothing more.

So, my answer is that there is no difference but syntax between *Ruby*
lambdas and blocks.  Knowing no Python, I can only assume there's no
significant difference there.

Chris