bit duration
The bit duration is the time for the representation of a coded binary digit.
The bit duration results from the ratio of seconds (s) to bits (s/bit) and is the reciprocal of the data rate, which is specified in bits per second (bit/s). If 4 microseconds (µs) are required to represent a coded bit, then the data rate is 0.25 Mbps.
In serial communication, bit duration is a relative unit of time measurement used to compare run times, e.g. inherent delay time, latency time.