Describing something that happens on-and-off over time. Something that recurs (though not necessarily regularly, or frequently) over time. Describing some activity that comes and goes, but always, eventually recurs.
In the context of artificial neural network learning strategies, the term online-learning
has come to mean the same thing as continual learning. It is usually not the same as continuous learning, which natural learning systems perform.
Continual is not
a synonym for Continuous
For more information please refer to: Continual vs Continuous