A set of data where observations on a variable or set of variables are collected over a well-defined sequence of time intervals. In traditional time-series, a single entity might be observed (i.e., N=1) over a long period of time (T>100). It is typical to use the time-series label when the data collection includes more time points than individuals (i.e., T>N).
See Autoregressive series/model, Ergodic, Hidden, Longitudinal design, Longitudinal-exeperimental studies, Longitudinal studies, Hidden Markov model (HMM). Stationarity, Time-adjacent observations