Final answer:
The correct term for the variation in the delay of packets in a network is Jitter, which is different from latency, throughput, and congestion.
Step-by-step explanation:
The term that defines a variation in the delay of packets in the network is Jitter. Jitter refers to the variability over time of the latency across a network. When data packets travel through a network to their destination, they can take different paths, and thus, some packets may experience more delay than others. This inconsistency can cause problems in real-time communications, such as VoIP or online gaming. On the other hand, latency is the time it takes for a packet to travel from source to destination. Throughput is the rate at which data is transferred across the network. Lastly, congestion refers to the overcrowding of network nodes with too much traffic, which can result in packet loss and delays.