General Book of the Tarot, by A. E. Thierens, , at sacred-texts.com
TRADITION: Society, association, alliance, multitude and all that implies a gathering of men, even armies; mixture; country life, felicity, augmentation, prosperity, happiness, peace and concord, etc., convocation; advance.
THEORY: It is Air on the Fourth house and the mixing of mercurial and lunar influence will of course explain the idea of gathering. We cannot quite see some of the definitions (contract, pact, treaty), but generally we find the idea of that which binds together by memory and common motives, thoughts, mottos common to a certain group of people, be it family or nation, clan or army. So this leads us to see in the card the expression of the common motive, of that which binds people together. It is not the contract, but the motive which afterwards leads to contracts, or from which the contract will result. A common mistake, in astrological descriptions as well, is this mixing up of definitions relating to the cause and to the effect respectively. Mercury
brooding over the house of the family and the moon, engenders homely feelings, memories, thoughts of internal service, household matters, and tends more or less to a profane and familiar or descriptive language, to joke, fun and the theatrical art, to inviting people to come together and have their share in weal and woe. It represents also common sense, which, however, remains in many cases 'common' enough. And it contains the motives, which actually govern the facts and actions in this world.
CONCLUSION: Family-spirit, clan, home, the ideas and motives which rule us, consequently that which is familiar to us; memory, reminiscences, brooding and scheming, fantasy, theatrical arts, fancy, imagination. It can be augmentation as well as decrease, it generally means change and unstable conditions, popularity and vaccillation, profanation. It may denote some group of people, a gathering or meeting, family-council. A convocation. a call and a vote. Cosiness.