Keywords are special words in Ruby which are reserved by the language and have predefined uses. Each keyword serves a different implementation than other. Let’s dive into these keywords and understand their definitions.

1. BEGIN -
   • Code inside BEGIN will run before any other code written in the current file.
     
2. END -
   • Code inside END will run after any other code written in the current file
     
3. alias -
   • alias helps to create an alias between two methods and It has lower precedence than && and is for short-circuit boolean
     
4. begin -
   • This Ruby keyword helps us to start an exception handling block
     
5. break -
   • It helps to leave a block early
     
6. case -
   • This Ruby keyword helps to start a case expression
     
7. class -
   • class helps user to create or opens a class in ruby
     
8. def -
   • def keyword in ruby helps us to define a function
     
9. defined? -
   • Defined? It describes its argument by returning a string
     
10. do -
    • This Ruby keyword helps to start a block of code
      
11. else -
    • Else is the unhandled condition in if and unless expression
      
12. elsif -
    • Elsif helps the user to give alternate conditions to if expression
      
13. end -
    • methods, modules, classes etc, use end. It indicates the end of a syntax block false False here means boolean false
      
14. ensure -
    • ensure is a block of code that will always run when an exception is raised
      
15. for -
    • To help us to create a loop for iteration
      
16. if -
    • Used as an expression for if or modifiers if
      
17. in -
    • It helps to separate iterable Objects and iterable variables in a for loop
      
18. module -
    • Helps us in creating or opening module
      
19. next -
    • Lets the user skips the rest of the code in the block
      
20. nil -
    • Nil represents false value indicating “no value” or “unknown.”
      
21. not -
    • It inverts the boolean expression but has less precedence than “!”
      
22. or -
    • It represents boolean or with less precedence than “||”
      
23. redo -
    • Redo helps to restart execution in the present block
      
24. rescue -
    • It helps to start an exception section of code in a beginning block
      
25. retry -
    • It helps us to retries an exception block
      
26. return -
    • To exit from a method
      
27. self -
    • Helps in calling Object of current method attached to
      
28. super -
    • It helps in calling the current method in a superclass
      
29. then -
    • In control structure, It represents the end of the conditional block
      
30. true -
    • true here is just a simple boolean true expression
      
31. undef -
    • It helps in preventing module or class from responding to the method call
      
32. unless -
    • It helps in creating unless and modifiers unless expressions
      
33. until -
    • Help us to create an iterative loop until a condition is met
      
34. when -
    • it helps by representing a condition in a case expression
      
35. while -
    • Help us to create an iterative loop while a condition is true
      
36. yield -
    • yield Helps to start execution of block send to the current method
      
37. ENCODING -
    • It represents script encoding of the current file
      
38. LINE -
    • It represents the line number of keywords in the current file
      
39. FILE -
    • It represents the path to the current file.

Happy Coding!!!