Tea is graded by leaf size and style. Orange Pekoe is the most famous of these sizes (although it is commonly misunderstood to be a type or flavor of tea!) Pekoe is derived from the Chinese word "Bai choe" which means white hair or down referring to the white downy hairs found on the bud leaves. The "Orange" part of the term is a mystery: One of the explanations is that the Chinese sometimes used to use orange blossoms to flavor their tea. Another reference to "orange" comes from the early days of tea trading and the Netherlands House of Orange, governing entity in 1815.
The funny thing about "orange pekoe" is that it is not a type of tea - it is a leaf size! In general, the leaf sizes (in the sub-continent) are described - from biggest to smallest - as follows:
Generally, the sizes work like this: OP - Pekoe or Orange Pekoe -- OP or OP1 (#1 quality) or OPA ("A" quality) - full large, wiry leaf.
FOP - Flowery Orange Pekoe- Smaller than OP but with some tips.
BOP - Broken Orange Pekoe - Smaller still, but still flaky broken leaf but can vary dramatically in size. (In Assam, they can be more than a few cm in size. In Sri Lanka they can be small enough to use in tea bags.
BOP Fannings - Literally, the stuff that they used to "fan" away from the bigger leaf. No kidding. (Tea has all kinds of cool and strange historical notes that crop up that never cease to amaze me.)
Pekoe Dust -Dust #1 and #2 - Just like it sounds Ð the stuff that goes in the tea bags.
Now lets be clear, as much as I am a full leaf tea drinker, dust from a great day in a great garden, is a heck of a lot better than dust from a poorer garden. But larger leaf tends to yield better, more complex flavor.
Some styles are described with other terms:
Flowery - referring to the shape of the leaf resembling a crushed flower because it is loosely rolled.
Tippy - a modifier used for whole and broken leaf grades indicating "tips" or buds in the tea.
Tips are the down-like white/yellow hair on the tip of the youngest tea leaves (two leaves and a bud!)
Golden-describes the color of the tips (highly sought after)
This whole thing results in some pretty fun acronyms for the really fancy grades of tea from India:
GFOP- Golden Flowery Orange Pekoe -An open OP leaf with a golden brown tip.
GFOP Tippy Golden Flowery Orange Pekoe- Like the GFOP but with more tips
FTGFOP Fancy Tippy Golden Flowery Orange Pekoe -Even higher quality
SFTGFOP Super fine Fancy Tippy Golden Flowery Orange Pekoe- Mostly golden tips of exceptional quality.
Confused? Me too! Just remember that Orange Pekoe has no orange in it!
CTCs also have grades but they range in size much smaller than the "orthodox" grades above.