Old English turf, tyrf "slab of soil and grass, sod," also "surface of grassland," from Proto-Germanic *turfa- (source also of Old Norse torf, Danish tørv, Old Frisian turf, Old High German zurba, German Torf), from PIE root *drebh- "to wind, compress" (source also of Sanskrit darbhah "tuft of grass").
Especially "the race course," hence the turf "the profession of racing horses" (1755). French tourbe "turf" is a Germanic loan-word. The Old English plural was identical with the singular, but in Middle English turves sometimes was used. Slang meaning "territory claimed by a gang" is attested from 1953 in Brooklyn, N.Y.; earlier it had a jive talk sense of "the street, the sidewalk" (1930s), which is attested in hobo use from 1899, and before that "the work and venue of a prostitute" (1860). Turf war is recorded from 1962.
"piece of turf or sod with the grass growing on it," used for roofing material, etc., 1530s, Scottish, of unknown origin. Also divet, diffat, devot, etc. The golfing sense "slice of turf cut out by the club in playing a stroke" is by 1884.
"flat stone for paving," c. 1600, ultimately from Old Norse flaga "stone slab," from Proto-Germanic *flago- (from extended form of PIE root *plak- (1) "to be flat"). Earlier in English as "piece cut from turf or sod" (mid-15c.), from Old Norse flag "spot where a piece of turf has been cut out," from flaga.
"turf, slice of earth with grass on it," mid-15c., apparently from Middle Dutch sode "turf," or Middle Low German sode, both related to Old Frisian satha "sod," all of uncertain origin. Perhaps the notion is water saturation and the group is related to sog. The (old) sod "Ireland" is from 1812.
"small particle, as of dust visible in a ray of sunlight," Old English mot, of unknown origin; perhaps related to Dutch mot "dust from turf, sawdust, grit," Norwegian mutt "speck, mote, splinter, chip." Hence, anything very small. Many references are to Matthew vii.3.
"grass-covered ground," c. 1300, from Old English sweard "skin, hide, rind" (of bacon, etc.), from Proto-Germanic *swarthu- (source also of Old Frisian swarde "skin of the head," Middle Dutch swarde "rind of bacon," Dutch zwoord "rind of bacon," German Schwarte "thick, hard skin, rind," Old Norse svörðr "walrus hide"). Meaning "sod, turf" developed from the notion of the "skin" of the earth (compare Old Norse grassvörðr, Danish grønsvær "greensward").
c. 1300, erbe "non-woody plant," especially a leafy vegetable used for human food, from Old French erbe "grass, herb, plant fed to animals" (12c., Modern French herbe), from Latin herba "grass, an herb; herbage, turf, weeds" (source also of Spanish yerba, Portuguese herva, Italian erba). The form of the English word was refashioned after Latin since 15c., but the h- was mute until 19c. Slang meaning "marijuana" is attested from 1960s. The native word is wort.