non-uniform delays that can cause packets to arrive and be processed out of sequence
NIST SP 800-58
The time or phase difference between the data signal and the ideal clock.
NIST SP 800-82 Rev. 2
The short-term variations of the significant instants of a timing signal from their ideal positions in time (where short-term implies that these variations are of frequency greater than or equal to 10 Hz).
NIST IR 8323r1 from ITU-T G.810
NIST IR 8401 from ITU-T G.810