The distinction between cards that (intrinsically) mean a particular thing and cards that merely support that particular thing can be important. I call those ‘support cards’ for that subject.

We find this out in practice, those of us who are avid about our Tarot, without making a big deal of it. Once in a while, though, a distinction makes a difference. Once in a while the fact that it’s (only) a support card changes what you read the whole spread as.

Let me tell you about my most frequent example. In my system, Four of Wands (whose illustration is a wedding) and Ten of Cups (whose illustration is mama and papa and the kids saluting their fine home on the corner lot with the rainbow arching over it) are leading cards for marriage.

Justice with either of these marriage cards makes the phrase ‘legal marriage.’ Very useful!

In real Tarot life (in practice) I find Justice coming up to infer that marriage is in the air, or that one or more of the parties in the couple is committed toward being married to the other. That’s in the absence of either Four of Wands or Ten of Cups. (In that same spread, you are likely to find, say Lovers, or Temperance, or even Knight of Cups or Six of Cups–romance cards to me.)

Support cards are something to keep in mind. They are weaker influences than the cards that are the main ones for that meaning. They tend to contribute nuances and details.