chai (n.)

"tea," 1590s, also chaw, ultimately from the Mandarin ch'a "tea;" used in English alongside tea when the beverage was introduced.

1650s, tay, "prepared leaves of the tea plant," also "an infusion of prepared tea leaves used as a beverage," also in early spellings thea, tey, tee and at first pronounced so as to rhyme with obey (Pope); pay (Gay). The modern pronunciation predominates from mid-18c.

The word is earliest in English as chaa (1590s), also cha, tcha, chia, cia (compare cha, chai). The two forms reflect two paths of transmission: chaa, etc. are from Portuguese cha, via Macao, from Mandarin (Chinese) ch'a. The later form, which became Modern English tea, is via Dutch thee, from Malay teh and directly from Chinese (Amoy dialect) t'e, which corresponds to Mandarin ch'a.

The modern English form (along with French thé, Spanish te, German Tee, etc.) reflects the role of the Dutch as chief importers of the leaves in that part of Europe (through the Dutch East India Company, from 1610). Meanwhile, Russian chai, Persian cha, Greek tsai, Arabic shay, and Turkish çay all came by overland trade routes from the Mandarin form.

Tea was known in Paris by 1635; the practice of drinking it was introduced in England by 1644. The word was extended by 1660s to the tea plant itself, also to similar infusions of the parts of other plants. The slang meaning "marijuana" (which sometimes was brewed in hot water) is attested by 1935, felt as obsolete by late 1960s.

The meaning "late afternoon meal at which tea is served" is by 1738. Tea-bottle as English slang for "old maid" is attested by 1909. To not do something for all the tea in China "not for anything" is colloquial, attested by 1947 in Australian English, said to date from 1890s.