The three that are most often wrong
FERMENTED, applied to black tea, is wrong — black tea is oxidised, and fermentation involves living microorganisms that only dark tea uses. UNOXIDISED, applied to white tea, is not quite right either, since slow oxidation occurs across the long wither. And LOW CAFFEINE, applied to white tea, is unsupported: bud-only grades use the part of the plant with the highest concentration.
Words that name a place, a process or a plant
Knowing which kind of word you are reading resolves a great deal. DARJEELING and ANXI are places. ORTHODOX and CTC are processes. QING XIN and YABUKITA are cultivars. GONGFU is a brewing approach. EARL GREY and ENGLISH BREAKFAST are recipes and name no origin at all. GAOSHAN is an elevation claim, and SI JI CHUN is a cultivar whose aroma imitates one.
The sensory vocabulary worth having
ASTRINGENCY is drying texture, not bitterness. UMAMI is savouriness from amino acids, most obvious in shaded Japanese green tea. HUI GAN is the returning sweetness that arrives seconds after swallowing, and it is what young pu-erh is judged on. CHA QI is a term drinkers use for bodily sensation beyond flavour; TeaHQ records that the word is used and takes no position on what causes it.
Terms that carry a premium and are hard to verify
LAO CONG means old bush and is unverifiable by a buyer. ZHENG YAN means the protected Wuyi core zone, which cannot supply a fraction of what is sold under it. GU SHU means old arbour and is the most abused claim in Yunnan. None of these is meaningless — each describes a real thing — but each appears on far more packaging than the underlying production can support.
Where to go next
The glossary carries twenty-nine terms with fuller definitions, the words each is confused with, and the wrong belief stated directly rather than left implied. Several entries exist because the common definition is wrong rather than because the word is obscure.