Step 1: Reframe around social distance:
Think of kinship degree as social distance from 'self': primary kin are at the innermost circle, secondary kin form the next ring outward, and tertiary kin the ring beyond that, with each ring carrying progressively weaker obligations and rights.
Step 2: Note the rules attached:
Different societies attach different rights, duties and marriage rules to each degree, for instance, marriage is typically prohibited among primary and many secondary kin, illustrating why the distinction between degrees matters practically, not just terminologically.
Final Answer:
Kinship can be pictured as concentric circles of closeness, primary (innermost), secondary, then tertiary, cross-cut by the consanguineal/affinal distinction, with each degree carrying its own social rights, obligations and marriage rules.