what is the meaning of def in python code example

Example 1: python def

# You can make a function by using the [def] keyword
def foo():
	print("Hello")

# You can run it by calling it as such
foo()

def add(numA, numB):
  print(numA+numB)
  # or 
  return numA+numB

num = add(1, 5)
print(num)

Example 2: python funtion

def nameOfFunction(something):
  	return something

Example 3: functions in python

#Function Tutoral:
def hello():
  print("hello")
"""To make a function, it needs def then nameOfFunction() and a : to 
make the function work, you don't need a closing tag, as long as there is
tabbed section."""

def add(a, b): #This time, there is two inputs for the function to prossess. 
  c = a + b 
  return c
"""What the function above does is you input 2 numbers, and then it returns 
#The Value c, Calling it is as simple as add(5, 1) 
#What return does, is it almost makes a varible. So you can do:
#70 + add(10, 20) and it will return with: 100. This is because it will
go 70 + 30, as the function returned 30 because the inputs were 10 and 20."""

"""Functions can be called by code, as long as the function has already
been defined. Hope this helped you in your python journey!"""

Example 4: explain def in python

def greet(name):
    """
    This function greets to
    the person passed in as
    a parameter
    """
    print("Hello, " + name + ". Good morning!")