send() in Ruby is used to call a method dynamically by its name as a string or symbol. Instead of calling a method directly like obj.some_method, you can use obj.send(:some_method), which is particularly useful when the method name is stored in a variable.
For example:
class Greeting
def hello
"Hello, world!"
end
end
g = Greeting.new
puts g.send(:hello) # Outputs "Hello, world!"
This is the same as calling g.hello, but send lets you choose the method dynamically.