Hash Rocket
The => symbol in the Ruby community is affectionately referred to as the hash rocket (maybe hashrocket too, though not to be confused with the consultancy ↗).
Not what you're looking for? The => symbol is also used as part of a rescue assignment.
Defining a hash in Ruby used to require the following syntax:
> {:ruby => :rails}
=> {:ruby=>:rails}
However, in 2007 with the release of Ruby 1.9, we got the colon syntax for symbol keys. Though this makes the hash rocket syntax disappear from a lot of code, we can still see it in IRB's response.
> {ruby: :rails}
=> {:ruby=>:rails}
We still need to use the hash rocket when defining non-symbol keys. If the colon is used with a string in a hash definition, the string will be coerced to a symbol.
> {"taco" => "bell"}
=> {"taco"=>"bell"}
> {"taco": "bell"}
=> {:taco=>"bell"}
The hash rocket syntax is required for any other kind of non-symbol key.
> { ['c',3] => 'Knight' }
=> {["c", 3]=>"Knight"}