void delay(unsigned long ms)
delay() pauses your program for ms milliseconds.
None
The delay() function is completely blocking. Nothing else can happen while delay() is running other than interrupts. Its use is discouraged for anything but short delays for timing purposes. Instead the use of millis() is encouraged to create non-blocking code.
delay() conforms to the Arduino 1.6.x API.
Wait for 1 second:
delay(1000);