( u -- )
Wait at least u milliseconds.
The actual length and variability of the time period depends upon the implementation-defined resolution of the system clock and upon other system and computer characteristics beyond the scope of this standard.
Although their frequencies vary, every system has a clock. Since many programs need to time intervals, this word is offered. Use of milliseconds as an internal unit of time is a practical "least common denominator" external unit. It is assumed implementors will use "clock ticks" (whatever size they are) as an internal unit and convert as appropriate.