The Collaborative International Dictionary of English v.0.48:

Agriculture \Ag"ri*cul`ture\ (?; 135), n. [L. agricultura; ager
   field + cultura cultivation: cf. F. agriculture. See Acre
   and Culture.]
   The art or science of cultivating the ground, including the
   harvesting of crops, and the rearing and management of live
   stock; tillage; husbandry; farming.
   [1913 Webster]

WordNet (r) 3.0 (2006):

agriculture
    n 1: a large-scale farming enterprise [syn: agribusiness,
         agriculture, factory farm]
    2: the practice of cultivating the land or raising stock [syn:
       farming, agriculture, husbandry]
    3: the federal department that administers programs that provide
       services to farmers (including research and soil conservation
       and efforts to stabilize the farming economy); created in
       1862 [syn: Department of Agriculture, Agriculture
       Department, Agriculture, USDA]
    4: the class of people engaged in growing food

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "agriculture":
   Ceres, Cora, Demeter, Dionysos, Dionysus, Flora, Frey, Gaea, Gaia,
   Kore, Persephassa, Persephone, Pomona, Proserpina, Proserpine,
   Triptolemos, Triptolemus, corn god, farming, fertility god,
   forest god, husbandry, vegetation spirit



Easton's 1897 Bible Dictionary:

Agriculture
   Tilling the ground (Gen. 2:15; 4:2, 3, 12) and rearing cattle
   were the chief employments in ancient times. The Egyptians
   excelled in agriculture. And after the Israelites entered into
   the possession of the Promised Land, their circumstances
   favoured in the highest degree a remarkable development of this
   art. Agriculture became indeed the basis of the Mosaic
   commonwealth.

     The year in Palestine was divided into six agricultural
   periods:-

     I. SOWING TIME.

     Tisri, latter half

     (beginning about the autumnal equinox.)

     Marchesvan.

     Kisleu, former half.

     Early rain due = first showers of autumn.

     II. UNRIPE TIME.

     Kisleu, latter half.

     Tebet.

     Sebat, former half.

     III. COLD SEASON.

     Sebat, latter half.

     Adar.

     [Veadar.]

     Nisan, former half.

     Latter rain due (Deut. 11:14; Jer. 5:24; Hos. 6:3; Zech. 10:1;

     James 5:7; Job 29:23).

     IV. HARVEST TIME.

     Nisan, latter half.

     (Beginning about vernal equinox. Barley green. Passover.)

     Ijar.

     Sivan, former half., Wheat ripe. Pentecost.

     V. SUMMER (total absence of rain)

     Sivan, latter half.

     Tammuz.

     Ab, former half.

     VI. SULTRY SEASON

     Ab, latter half.

     Elul.

     Tisri, former half., Ingathering of fruits.

     The six months from the middle of Tisri to the middle of Nisan
   were occupied with the work of cultivation, and the rest of the
   year mainly with the gathering in of the fruits. The extensive
   and easily-arranged system of irrigation from the rills and
   streams from the mountains made the soil in every part of
   Palestine richly productive (Ps. 1:3; 65:10; Prov. 21:1; Isa.
   30:25; 32:2, 20; Hos. 12:11), and the appliances of careful
   cultivation and of manure increased its fertility to such an
   extent that in the days of Solomon, when there was an abundant
   population, "20,000 measures of wheat year by year" were sent to
   Hiram in exchange for timber (1 Kings 5:11), and in large
   quantities also wheat was sent to the Tyrians for the
   merchandise in which they traded (Ezek. 27:17). The wheat
   sometimes produced an hundredfold (Gen. 26:12; Matt. 13:23).
   Figs and pomegranates were very plentiful (Num. 13:23), and the
   vine and the olive grew luxuriantly and produced abundant fruit
   (Deut. 33:24).

     Lest the productiveness of the soil should be exhausted, it
   was enjoined that the whole land should rest every seventh year,
   when all agricultural labour would entirely cease (Lev. 25:1-7;
   Deut. 15:1-10).

     It was forbidden to sow a field with divers seeds (Deut.
   22:9). A passer-by was at liberty to eat any quantity of corn or
   grapes, but he was not permitted to carry away any (Deut. 23:24,
   25; Matt. 12:1). The poor were permitted to claim the corners of
   the fields and the gleanings. A forgotten sheaf in the field was
   to be left also for the poor. (See Lev. 19:9, 10; Deut. 24:19.)
   Agricultural implements and operations.

     The sculptured monuments and painted tombs of Egypt and
   Assyria throw much light on this subject, and on the general
   operations of agriculture. Ploughs of a simple construction were
   known in the time of Moses (Deut. 22:10; comp. Job 1:14). They
   were very light, and required great attention to keep them in
   the ground (Luke 9:62). They were drawn by oxen (Job 1:14), cows
   (1 Sam. 6:7), and asses (Isa. 30:24); but an ox and an ass must
   not be yoked together in the same plough (Deut. 22:10). Men
   sometimes followed the plough with a hoe to break the clods
   (Isa. 28:24). The oxen were urged on by a "goad," or long staff
   pointed at the end, so that if occasion arose it could be used
   as a spear also (Judg. 3:31; 1 Sam. 13:21).

     When the soil was prepared, the seed was sown broadcast over
   the field (Matt. 13:3-8). The "harrow" mentioned in Job 39:10
   was not used to cover the seeds, but to break the clods, being
   little more than a thick block of wood. In highly irrigated
   spots the seed was trampled in by cattle (Isa. 32:20); but
   doubtless there was some kind of harrow also for covering in the
   seed scattered in the furrows of the field.

     The reaping of the corn was performed either by pulling it up
   by the roots, or cutting it with a species of sickle, according
   to circumstances. The corn when cut was generally put up in
   sheaves (Gen. 37:7; Lev. 23:10-15; Ruth 2:7, 15; Job 24:10; Jer.
   9:22; Micah 4:12), which were afterwards gathered to the
   threshing-floor or stored in barns (Matt. 6:26).

     The process of threshing was performed generally by spreading
   the sheaves on the threshing-floor and causing oxen and cattle
   to tread repeatedly over them (Deut. 25:4; Isa. 28:28). On
   occasions flails or sticks were used for this purpose (Ruth
   2:17; Isa. 28:27). There was also a "threshing instrument" (Isa.
   41:15; Amos 1:3) which was drawn over the corn. It was called by
   the Hebrews a moreg, a threshing roller or sledge (2 Sam. 24:22;
   1 Chr. 21:23; Isa. 3:15). It was somewhat like the Roman
   tribulum, or threshing instrument.

     When the grain was threshed, it was winnowed by being thrown
   up against the wind (Jer. 4:11), and afterwards tossed with
   wooden scoops (Isa. 30:24). The shovel and the fan for winnowing
   are mentioned in Ps. 35:5, Job 21:18, Isa. 17:13. The refuse of
   straw and chaff was burned (Isa. 5:24). Freed from impurities,
   the grain was then laid up in granaries till used (Deut. 28:8;
   Prov. 3:10; Matt. 6:26; 13:30; Luke 12:18).