"Tarot" refers to a family of games played with an augmented deck, (that is, decks with a fifth "suit" serving as permanent trumps), and also to the decks themselves. Most other card games using trumps select one of four regular suits to serve as trumps for a particular hand.
"Tarot" (these days) also refers to similar decks that are used for fortune-telling and other esoteric purposes. In English-speaking countries, despite a slow but growing interest in Tarot's gaming heritage, fortune-telling is currently the only common use of Tarot cards, but their origin is merely a card game such as "go fish" that were just that for 350 years before they were used as divination tools.
the Tarot deck consisted of a regular 56-card deck, augmented with a hierarchy of 22 allegorical trump cards. This created the standard 78-card Tarot deck, originally referred to as "carte da trionfi," cards with trumps.
In 1540 Francesco Marcolini published in Venice a fortune book that can be considered the first known document about cartomancy (using cards for magic.) The cards that were used in the divination process were not tarot and actually played a rather marginal role.
The Church never spoke against Tarot, and the one known sermon (16th century) which strongly condemns Tarot, along with dice and regular playing cards, does not suggest that Tarot was anything other than a game of chance. The confused preacher denounces Tarot for its moral allegory in which the Emperor and Pope are subject to the same fate as the rest of mankind. (To me this suggest that they are almost god-like, which is a contradiction of the religion in itself, but more importantly reminds me of the mindset of the people of ancient Egypt.)
In the later 18th century Fortune-telling with playing cards had developed from their use as a randomizing device to pick a page in a book of fortunes in the 1500s, through the use of special fortune-telling decks in the 1600s, and finally to the point of regular decks being given symbolic meaning in the 1700s. A few scattered indications of this appear earlier in the century, but the first book on cartomancy was published in 1770. It was written by Etteilla, the world's first professional cartomancer, who became one of the founders of occult Tarot. In the 1780s he and two other French writers developed much of the occult lore and fortune-telling methods that would reinvent Tarot in the late 1800s.
These three writers changed Tarot forever. Neither knowing nor caring much about Tarot's 350-year history, its original and common use as a game, or the intended meaning of its allegorical cycle, they interpreted the images freely. They used the twenty-two trumps as signs designating the twenty-two letters of the Hebrew alphabet. These newly-minted correspondences made the Tarot deck into a novel emblem system for Cabalistic magic and mysticism. The two esoteric uses, Cabala and divination, became permanently attached to Tarot. The authors of this newly invented Tarot also wrote up a detailed fantasy about Tarot's origin and history, involving Egyptian initiations, Jewish mystics, and vagabond Gypsies. These fictional histories were intended to validate the correspondences the occultists had devised, by appeal to alleged ancient wisdom and secret traditions.
In addition to fortune telling, modern Tarot applications include soul-searching exercises and meditation for personal growth, and as a randomized input for free association and brainstorming techniques. Not surprisingly, they have even been used by some psychologists in a therapeutic context. The main distinctions between Waite and the contemporary Tarot enthusiasts are specificity and authority. Waite was in some ways closer to the earlier occultists who saw and emphasized a particular design to the trumps and their sequence, rather than the contemporary approach which validates any intuition one might posit about what are seen as archetypal subjects. Waite's authority for his design was personal insight and the history of Christian mysticism, whereas the contemporary Tarotist is likely to cite C.G. Jung and neo-Jungian psychologists.
We have all had the experience where we already knew something but weren't sure we knew it until someone told us and we realize we already knew it. It's just a brain storming tool so stop giving in to people judging you and let's call it what it is.