1) Bad service 2) Court infraction 3) Mistake in tennis 4) San andreas and san gabriel 5) Tennis service setback 6) Tennis terminology 7) Wimbledon error 
The term `double fault” can refer to: ... On the x86 architecture, a double fault exception occurs if the processor encounters a problem while trying to service a pending interrupt or exception. An example situation when a double fault would occur is when an interrupt is triggered but the segment in which the interrupt handler resides is invalid. If the processor encounters a problem when...
Two faults in a row in one point, causing the player serving to lose the point.
When your serve is called out two times in a row.
two missed serves in a row. The server will lose the point.
two faults in a row in one point, causing the player serving to lose the point
[n] - (tennis) two successive faults in serving resulting in the loss of the point
noun (tennis) two successive faults in serving resulting in the loss of the point
If the server fails to serve correctly on both 1st and 2nd serves this is called a Double Fault. The server then loses this point.
(in tennis, squash, handball, etc.) two faults in succession, resulting in the loss of the point, the loss of the serve, or both.