Dynamic system	A system that evolves over time, described in mathematical terms by a system of differential equations that represent the time evolution of the state variables in the phase space, where each axis is associated with a state variable and each point in the space represents a possible state configuration.
Steady states (equilibria)	Values of the state variables obtained by setting the time derivatives to zero in the system of differential equations and solving the corresponding algebraic system. If the system is at an equilibrium at a certain time, it will remain at the same equilibrium unless an external perturbation occurs.
Monostable, bistable, multistable systems	An equilibrium is stable if the system, after having moved away from this equilibrium due to a (sufficiently small) external perturbation, goes back to the equilibrium. Monostable systems admit only one stable equilibrium, bistable systems exactly two, and multistable systems more than two.
Bifurcation parameter	A parameter present in the differential equations that is varied when computing a bifurcation diagram.
Bifurcation diagram	It is the diagram that shows the values and the stability properties of the system equilibria for different values of a bifurcation parameter, and thus reveals whether a bifurcation (i.e., a change in the number of equilibria and/or in their stability properties) occurs. We call bifurcation value the value of the bifurcation parameter at which the system undergoes a bifurcation (for instance, transitioning from monostability to multistability).
Phase portrait	Graphical representation of the trajectories of a dynamic system during its time evolution starting from given initial conditions. Each point of a trajectory represents the values of the state variables (i.e., their Cartesian coordinates) at a different time instant.
Initial condition	It is the starting point of a trajectory, namely, the configuration in which the system happens to find itself at the beginning of its time evolution. In the analysis of dynamic systems, the initial conditions are typically assumed to be determined by factors that are external to the model (perturbing events).
Basin of attraction of a given steady state	Set of initial conditions starting from which the system trajectories reach the given steady state. Depending on the starting point, the system will converge to one of the stable steady states. Each steady state has its own basin of attraction and there is no overlapping among different basins of attraction. A system trajectory is attracted by a certain stable steady state when it starts sufficiently close to it (namely, within its basin of attraction).