If by “solid” and “discrete” line of relationship/correlation among occurrences you mean the terminology for describing how strongly occurrences are connected, the distinction can be expressed like this: Solid relationship / correlation — the occurrences have a clear, consistent, and relatively strong connection . When one occurs, the other tends to occur in a predictable way. Discrete relationship / correlation — the occurrences are separate or distinguishable , with the relationship occurring only under particular conditions or between particular occurrences. “Discrete correlation” is less standard terminology and may need a more precise term depending on your field. If you're looking for a single technical phrase meaning a clear and continuous connection among occurrences , possibilities include “strong association,” “systematic relationship,” “consistent correlation,” “direct relationship,” or “robust correlation.” If you tell me the field/context (e.g., philosop...