The word is from Latin pocillum, a little cup or a small cupful. This has given us a few rare and obsolete words, such as pocill, a draught or potion, pocilliform (shaped like a cup), pocillator (a cup-bearer), and pocillation (the action of bearing a cup).
Pocillovy and its linked term pocillovist, on the other hand, are modern creations. An article in the Financial Times in May 1984 claimed that Winnie Freeman, a housewife and collector of Reigate in Surrey, invented the former word, basing it on the Latin pocillum ovi, a small cup for an egg. She used it in the title for her little monograph on the hobby of collecting eggcups.
A word of narrow focus and specialist appeal, pocillovy is rare enough that no dictionary has yet opened its pages to admit it, although it may be found among aficionados of this hobby and in occasional news items. It’s an odd-looking term, which emphasises its essential weirdness, since the only common English words that end in -ovy are anchovy, groovy and Muscovy.