Old English æcer "tilled field, open land," from Proto-Germanic *akraz "field, pasture" (source also of Old Norse akr, Old Saxon akkar, Old Frisian ekker, Middle Dutch acker, Dutch akker, Old High German achar, German acker, Gothic akrs "field"), from PIE root *agro- "field."
"[O]riginally 'open country, untenanted land, forest'; ... then, with advance in the agricultural state, pasture land, tilled land, an enclosed or defined piece of land" [OED]. In English at first without reference to dimension; in late Old English the amount of land a yoke of oxen could plow in a day, afterward defined by statute 13c. and later as a piece 40 poles by 4, or an equivalent shape [OED cites 5 Edw. I, 31 Edw. III, 24 Hen. VIII]. The older sense is retained in God's acre "churchyard." Adopted early in Old French and Medieval Latin, hence the Modern English spelling, which by normal development would be *aker (compare baker from Old English bæcere).
It forms all or part of: acorn; acre; agrarian; agriculture; agriology; agro-; agronomy; onager; peregrinate; peregrination; peregrine; pilgrim; stavesacre.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit ajras "plain, open country," Greek agros "field," Latin ager (genitive agri) "a field," Gothic akrs, Old English æcer "field."
The sense was gradually restricted in Low German, Scandinavian, and English to the most important of the forest produce for feeding swine: the mast of the oak tree. The regular modern form would be *akern; the current spelling emerged 15c.-16c. by folk etymology association with oak (Old English ac) and corn (n.1), neither of which has anything to do with it. Acorn squash is attested by 1937.
word-ending that sometimes distinguish British from American English. In the U.S., the change from -re to -er (to match pronunciation) in words such as fibre, centre, theatre began in late 18c. and became standard there over the next 25 years at the urging of Noah Webster (the 1804 edition of his speller, and especially his 1806 dictionary). The -re spelling, like -our, however, had the authority of Johnson's dictionary behind it and was unmoved in Britain, where it came to be a point of national pride, contra the Yankees.
Despite Webster's efforts, -re was retained in words with -c- or -g- (such as ogre, acre, the latter of which Webster insisted to the end of his days ought to be aker, and it was so printed in editions of the dictionary during his lifetime). The -re spelling generally is more justified by conservative etymology, based on French antecedents. It is met today in the U.S. only in Theatre as an element in the proper names of entertainment showplaces, where it is perhaps felt to inspire a perception of bon ton.
"measure of land equal to a square lineal perch" (usually 160 to the acre), late 14c., earlier "land-measuring rod" (c. 1300), from Old French perche "unit of linear measurement" (5.5 yards), also "measuring rod, pole, bar" used to measure this length (13c.), from Latin pertica "pole, long staff, measuring rod," which is related to Oscan perek "pole," Umbrian perkaf "twigs, rods." The same word as perch (n.1).
1819, "wheeled vehicle propelled by alternate thrusts of each foot on the ground," 1819, from French vélocipède (19c.), from Latin velox (genitive velocis) "swift, speedy" (see velocity) + pedem, accusative of pes "foot" (from PIE root *ped- "foot"). The mechanical ancestor of the bicycle, it was tinkered with and improved; the name continued for some time and was applied to an early kind of modern bicycle or tricycle from 1849. See bicycle (n.).
The Velocipede has been introduced into England, under letters patent, by Mr. Johnson, a coachmaker in Long-Acre, by whom it has been greatly improved, both in lightness and strength. "The road from Ipswich to Whitton," says the Bury paper, "is travelled every evening by several pedestrian hobby-horses; no less than six are seen at a time, and the distance, which is 3 miles, is performed in 15 minutes." [The Athenaeum, May 1, 1819]
late 13c., "a step in walking," also "rate of motion; the space traveled by the foot in one completed movement in walking," from Old French pas "a step, pace, trace," and directly from Latin passus, passum "a step, pace, stride," noun use of past participle of pandere "to stretch (the leg), spread out," probably from PIE *pat-no-, nasalized variant form of root *pete- "to spread."
It also was, from late 14c., a lineal measurement of vague and variable extent, representing the space naturally traversed by the adult human foot in walking. In some places and situations it was reckoned as the distance from the place where either foot is taken up, in walking, to that where the same foot is set down again (a great pace), usually 5 feet or a little less. The pace of a single step (military pace) is about 2.5 feet.
To keep pace (with) "maintain the same speed, advance at an equal rate" is from 1580s. Pace-setter "one who establishes trends in fashion," is by 1895; it also had literal meanings.
It is customary for the contractor to employ some expert as a pace setter. A man who can thin an acre of beets a day commands as high as $2.00 per day as a pace setter. The other employees are paid in the proportion their work bears to that of the pace setter. The weak, lazy and unskillful get the smallest wage. Besides that the contractor runs a commissary department and feeds the gang. They sleep in tents or in the shade of trees near where they work. [report on Oxnard, Calif., beet harvesting in "The Louisiana Planter and Sugar Manufacturer," May 13, 1899]