Online Etymology Dictionary

marijuana: 1918, alt. by influence of Sp. proper name Maria Juana "Mary Jane" from mariguan (1894), from Mex.Sp. marihuana, of uncertain origin.
"Marijuana ... makes you sensitive. Courtesy has a great deal to do with being sensitive. Unfortunately marijuana makes you the kind of sensitive where you insist on everyone listening to the drum solo in Iron Butterfly's 'In-a-Gadda-Da-Vida' fifty or sixty times." [P.J. O'Rourke, "Modern Manners," 1983]
pot (2): "marijuana," 1938, probably a shortened form of Mexican Sp. potiguaya "marijuana leaves."
reefer: "marijuana cigarette," 1920s, perhaps an alteration of Mex.Sp. grifo "marijuana, drug addict;" or perhaps from reef (2), on resemblance to a rolled sail.
toke (n.): 1968, "inhalation of a marijuana cigarette or pipe smoke," U.S. slang, from earlier verb meaning "to smoke a marijuana cigarette" (1952), perhaps from Sp. tocar in sense of "touch, tap, hit" or "get a shave or part." In 19c. the same word in British slang meant "small piece of poor-quality bread," but this probably is not related.
sinsemilla: potent strain of marijuana, 1975, from Mex.Sp., lit. "without seed."
muggle: "marijuana, a joint," 1926, originally mainly from New Orleans, of unknown origin.
dagga: "marijuana," 1660s, from Afrikaans, from Hottentot dachab "cannabis sativa smoked as a narcotic."
bong: "water pipe for marijuana," 1960s, U.S. slang, said to have been introduced by Vietnam War veterans, said to be from Thai baung, lit. "cylindrical wooden tube."
Thai: 1808, native name, from Tai, lit. "free." Thai stick "Asian marijuana cigarette" is attested by 1976.
roach (1): 1837, shortened form of cockroach (q.v.), in contemporary writing said to be from a polite desire to avoid the sexual connotation in the first syllable; meaning "butt of a marijuana cigarette" is first recorded 1938, perhaps from resemblance to the insect, but perhaps a different word entirely.
panama hat: hat made from the leaves of the screw pine, 1833, a misnomer, since it is originally made in Ecuador, but perhaps so called in Amer.Eng. because it was distributed north from Panama City. Panama red as a variety of Central Amer. marijuana is attested from 1967.
weed (n.): "plant not valued for use or beauty," O.E. weod, uueod "grass, herb, weed," from P.Gmc. *weud- (cf. O.S. wiod, E.Fris. wiud), of unknown origin. Meaning "tobacco" is from 1606; that of "marijuana" is from 1920s. The verb meaning "to clear the ground of weeds" is late O.E. weodian.
munch (v.): late 14c., mocchen, imitative (cf. crunch), or perhaps from O.Fr. mangier, from L. manducare "to chew." Related: Munched; munching. Munchies "food or snack" is first attested 1959; sense of "craving for food after smoking marijuana" is first attested 1971.
hemp: O.E. hænep, from P.Gmc. *hanapiz (cf. O.S. hanap, O.N. hampr, O.H.G. hanaf, Ger. Hanf), probably a very early Gmc. borrowing of the same Scythian word that became Gk. kannabis (see cannabis). Slang sense of "marijuana" dates from 1940s; though scientific use for the narcotic derived from hemp dates to 1870.
Acapulco: in full, Acapulco de Juarez, resort town in western Mexico, from Nahuatl (Aztec) acapulco "place of the large canes," from aca(tl) "cane (plant)" + -pul "large" + -co "place." Acapulco gold as the name of a local grade of potent marijuana is attested from 1965.
Mary: fem. proper name, O.E. Maria, Marie, "mother of Jesus," from L. Maria, from Gk. Mariam, Maria, from Aram. Maryam, from Heb. Miryam, sister of Moses (Ex. xv.), of unknown origin, said to mean lit. "rebellion." Nursery rhyme "Mary had a Little Lamb" written early 1830 by Sarah Josepha Hale of Boston; published Sept. 1830 in "Juvenile Miscellany," a popular magazine for children. Mary Jane is 1921 as the proprietary name of a kind of low-heeled shoe worn chiefly by young girls, 1928 as slang for marijuana.
joint (n.): late 13c., "a part of a body where two bones meet and move in contact with one another," from O.Fr. joint, from L. junctus, pp. of jungere "join" (see jugular). Slang meaning of "place, building, establishment" (esp. one where persons meet for shady activities) first recorded 1877, Amer.Eng., from an earlier Anglo-Irish sense (1821), perhaps on the notion of a side-room, one "joined" to a main room. The original U.S. sense was especially of "an opium-smoking den." Meaning "marijuana cigarette" (1938) is perhaps from notion of something often smoked in common, but there are other possibilities; earlier joint in drug slang meant "hypodermic outfit" (1935). Meaning "prison" is from 1953.
grass: O.E. græs, gærs "herb, plant, grass," from P.Gmc. grasan (cf. O.N., Ger., Goth. gras), from PIE *ghros- "young shoot, sprout," from base *gro-/*gre- "that which grows" (cf. L. gramen "grass"); related to grow and green. Sense of "marijuana" is first recorded 1938, Amer.Eng. Grasshopper is O.E. gærshoppa (cf. M.Swed. gräshoppare, Ger. Grashüpfer); as a term of reproach, from Eccl. xii.5. Grass widow (1528) was originally "discarded mistress" (cf. Ger. Strohwitwe, lit. "straw-widow"), probably in allusion to casual bedding. Sense of "married woman whose husband is absent" is from 1846.
"[G]rasse wydowes ... be yet as seuerall as a barbours chayre and neuer take but one at onys." [More, 1528]
blunt: c.1200, "dull, obtuse," perhaps from O.N. blundra (see blunder). Meaning "abrupt of speech or manner" is from 1580s. Blunt, street slang for "marijuana and tobacco cigar" (easier to pass around, easier to disguise, and the stimulant in the tobacco enhances the high from the pot) surfaced c.1993, but is said to have originated among Jamaicans in New York City in the early 1980s; from Phillies Blunt brand cigars.
"Users say that the Phillies Blunt brand produces less harsh-tasting or sweeter smoke. The leaf wrapper of a Phillies Blunt is strong enough to hold together through the manipulations of making a blunt. Other brands fall apart." [http://nepenthes.lycaeum.org/Drugs/THC/Smoke/blunts.html]
tea: 1655, earlier chaa (1598, from Port. cha), from Malay teh and directly from Chinese (Amoy dialect) t'e, in Mandarin ch'a. The distribution of the different forms of the word reflects the spread of use of the beverage. The modern Eng. form, along with Fr. thé, Sp. te, Ger. Tee, etc., derive via Du. thee from the Amoy form, reflecting the role of the Dutch as the chief importers of the leaves (through the Dutch East India Company, from 1610). First known in Paris 1635, the practice of drinking tea was first introduced to England 1644. The Port. word (attested from 1559) came via Macao; and Rus. chai, Pers. cha, Gk. tsai, Arabic shay, and Turk. çay all came overland from the Mandarin form. Meaning "afternoon meal at which tea is served" is from 1738. Slang meaning "marijuana" (which sometimes was brewed in hot water) is attested from 1935, felt as obsolete by late 1960s. Tea bag first recorded 1940; tea ball is from 1895.