Orange Pekoe is a classification of black tea based upon the origin of the leaf. To be classified as pekoe, the tea must be composed purely of the new flushes - a flush being the flower bud plucked with two youngest leaves. (Any other leaves produce teas of lower quality.)
The word "pekoe" comes from the Chinese ba hwa "white flower", and refers to the flower bud content of pekoe tea. Other source claimed that the word "pekoe" comes from an Amoy word for the special kind of Chinese tea (白毫茶). The original Amoy name was pronounced "Pek-ho" but the English word has corrupted into "Pee-Ko" nowadays. The name means white downy hair. The term refers to the down-like white "hairs" on the tea leaves that are the youngest and smallest on the tea plant. The Chinese Pekoe teas are classified into various qualities according to whether the adjacent young leaves (two, one or none) were picked along with the leaf buds. Top quality pekoe consists of only the leaf buds. The buds are picked using only the balls of the finger tips. Finger nails or mechanical tools are not used to avoid bruising the picks.
A common misconception is that Orange Pekoe is a type of tea with an orange flavor, or that is otherwise somehow associated with the orange fruit. In fact, however, Orange Pekoe has nothing at all to do with the tea's flavor.
There are generally three popular explanations given for the meaning of "Orange" in Orange Pekoe, none of them definitive. Possibly the most popular explanation is that it refers to the Dutch noble House of Orange-Nassau, the Dutch having had a central role in bringing tea to Europe. A second explanation is that it refers to a supposed Chinese practice of using orange blossoms to flavor tea. (In reality it's more customary to use jasmine blossoms, and only for green tea.) Finally, a third explanation is that it refers to the color of the leaves when they are harvested, which is wrong.
The actual explanation, however, is apparently the orange-yellow coloration of the dried tea flower buds, very conspicuous among the dried leaves. It is the same origin as that of the "Golden" tea grade (see below).
When crushed to make bagged teas, the tea is referred to as "broken", as in "Broken Orange Pekoe" (or "Broken Pekoe"), sometimes sold as loose leaf for reduced price. Bagged teas often also include fannings and dust, which are simply tiny remnants of the sorting and/or crushing process.
Orange Pekoe is often referred to as "OP"; the grading scheme contains several other categories considered to be of higher quality than OP. The grades for whole leaf orthodox black tea, in ascending order are:
OP (Orange Pekoe)
FOP (Flowery Orange Pekoe)
GFOP (Golden Flowery Orange Pekoe)
TGFOP (Tippy Golden Flowery Orange Pekoe)
FTGFOP (Fine Tippy Golden Flowery Orange Pekoe)
SFTGFOP (Super Fine Tippy Golden Flowery Orange Pekoe)
Sometimes a digit "1" or "2" is added to the grade, signifying the first or second flush: e.g., "FTGFOP1". (Only the first two flushes are used to make grade tea.)
Broken, Fannings and Dust orthodox teas have slightly different gradings. CTC teas have a yet different grading system.
A common joke among tea aficionados is that "FTGFOP" actually stands for "Far Too Good For Ordinary People".