Upright the Three of Cups is read as celebration, friendship and joy multiplied by being shared; reversed, as overindulgence, gossip, or a group that has curdled from support into something more like a crowd working against one of its own members.
The reversed reading is worth some care, since Waite's own printed meaning for it is comparatively narrow, excess and pleasure carried too far, without the gossip or social exclusion many modern readers now emphasize. The specifically social reading of the reversed card, three becoming a clique rather than three becoming too much wine, reflects a later shift in emphasis, one that tracks a broader move across the twentieth century toward reading the small cards for relationship dynamics rather than for events or fortunes as earlier cartomancers generally did.
Because the image shows exactly three figures, the card is also commonly used, more than most numbered cards, in questions that involve a third party or a group dynamic specifically, celebration or conflict alike; a reader working a spread about a friendship or a family will often reach for this card's reversed meaning first when a triangle of some kind is suspected, even where the question was not phrased in those terms.
Its upright sense, kept consistent across every source from Waite forward, remains among the least disputed in the deck: shared success is better than solitary success, and the card rewards company over withdrawal.