What is the meaning of timeout when i open a serial port on python.

Recently ive been working with my arduino uno and it has been an wonderful experience so far. Today im making a python
script to get data from a sensor and register it and save it on a file, along the way i noticed on a site that when
they open the serial port on python side:

arduino = serial.Serial("/dev/ttyACM0",timeout=1)

They have this timeout value. What does it mean ? Ive been playing with it, and when i set a number bigger than 5( bigger than the velocity at which im receiving the data from sensor (once every 5 seconds) I stop receiving data. Can somebody clarify me?

Im just asking this out of sheer curiosity.

(deleted)

Maybe pySerial API — pySerial 3.4 documentation has the answer.

Found with google serial.serial :wink: