1.  A number of beasts assembled together; as, a herd of horses, oxen, cattle, camels, elephants, deer, or swine; a particular stock or family of cattle. [1913 Webster]
" Herd is distinguished from flock, as being chiefly applied to the larger animals. A number of cattle, when driven to market, is called a drove." [1913 Webster]
"The lowing herd wind slowly o'er the lea." [1913 Webster]

2.  A crowd of low people; a rabble. [1913 Webster]
"But far more numerous was the herd of such
Who think too little and who talk too much." [1913 Webster]
"You can never interest the common herd in the abstract question." [1913 Webster]

   One who herds or assembles domestic animals; a herdsman; -- much used in composition; as, a shepherd; a goatherd, and the like. Chaucer. [1913 Webster]

1.  To unite or associate in a herd; to feed or run together, or in company; as, sheep herd on many hills. [1913 Webster]

2.  To associate; to ally one's self with, or place one's self among, a group or company. [1913 Webster]
"I'll herd among his friends, and seem
One of the number." [1913 Webster]

3.  To act as a herdsman or a shepherd. [1913 Webster]

   To form or put into a herd. [1913 Webster]

herd, n. & v.
--n.
1 a large number of animals, esp. cattle, feeding or travelling or kept together.
2 (prec. by the) derog. a large number of people; a mob (prefers not to follow the herd).
3 (esp. in comb.) a keeper of herds; a herdsman (cowherd).
--v.
1 intr. & tr. go or cause to go in a herd (herded together for warmth; herded the cattle into the field).
2 tr. tend (sheep, cattle, etc.) (he herds the goats).

Idiom:
herd-book a book recording the pedigrees of cattle or pigs. the herd instinct the tendency of associating or conforming with one's own kind for support etc. ride herd on US keep watch on.

Derivative:
herder n.

Etymology:
OE heord, (in sense 3) hirdi, f. Gmc

N  assemblage, collection, collocation, colligation, compilation, levy, gathering, ingathering, muster, attroupement, team, concourse, conflux, congregation, contesseration, convergence, meeting, levee, reunion, drawing room, at home, conversazione, assembly, congress, convention, conventicle, gemote, conclave, posse, posse comitatus, Noah's ark, miscellany, collectanea, museum, menagerie, museology, crowd, throng, group, flood, rush, deluge, rabble, mob, press, crush, cohue, horde, body, tribe, crew, gang, knot, squad, band, party, swarm, shoal, school, covey, flock, herd, drove, atajo, bunch, drive, force, mulada, remuda, roundup, array, bevy, galaxy, corps, company, troop, troupe, task force, army, regiment, host, populousness, clan, brotherhood, fraternity, sorority, association, volley, shower, storm, cloud, group, cluster, Pleiades, clump, pencil, set, batch, lot, pack, budget, assortment, bunch, parcel, packet, package, bundle, fascine, fasces, bale, seron, seroon, fagot, wisp, truss, tuft, shock, rick, fardel, stack, sheaf, haycock, fascicle, fascicule, fasciculus, gavel, hattock, stook, accumulation, congeries, heap, lump, pile, rouleau, tissue, mass, pyramid, bing, drift, snowball, snowdrift, acervation, cumulation, glomeration, agglomeration, conglobation, conglomeration, conglomerate, coacervate, coacervation, coagmentation, aggregation, concentration, congestion, omnium gaterum, spicilegium, black hole of Calcutta, quantity, collector, gatherer, whip, whipper in, assembled, closely packed, dense, serried, crowded to suffocation, teeming, swarming, populous, as thick as hops, all of a heap, fasciculated cumulative, the plot thickens, acervatim, tibi seris tibi metis.

VB  assemble, collect, muster, meet, unite, join, rejoin, cluster, flock, swarm, surge, stream, herd, crowd, throng, associate, congregate, conglomerate, concentrate, precipitate, center round, rendezvous, resort, come together, flock get together, pig together, forgather, huddle, reassemble, assemble, muster, bring together, get together, put together, draw together, scrape together, lump together, collect, collocate, colligate, get, whip in, gather, hold a meeting, convene, convoke, convocate, rake up, dredge, heap, mass, pile, pack, put up, truss, cram, acervate, agglomerate, aggregate, compile, group, aggroup, concentrate, unite, collect into a focus, bring into a focus, amass, accumulate, collect in a dragnet, heap Ossa upon Pelion.

N  multitude, numerous, numerosity, numerality, multiplicity, profusion, legion, host, great number, large number, round number, enormous number, a quantity, numbers, array, sight, army, sea, galaxy, scores, peck, bushel, shoal, swarm, draught, bevy, cloud, flock, herd, drove, flight, covey, hive, brood, litter, farrow, fry, nest, crowd, lots, all in the world and his wife, greater number, majority, multiplication, multiple, many, several, sundry, divers, various, not a few, Briarean, a hundred, a thousand, a myriad, a million, a quadrillion, a nonillion, a thousand and one, some ten or a dozen, some forty or fifty, half a dozen, half a hundred, very many, full many, ever so many, numerous, numerose, profuse, in profusion, manifold, multiplied, multitudinous, multiple, multinominal, teeming, populous, peopled, crowded, thick, studded, galore, thick coming, many more, more than one can tell, a world of, no end of, no end to, cum multis aliis, thick as hops, thick as hail, plenty as blackberries, numerous as the stars in the firmament, numerous as the sands on the seashore, numerous as the hairs on the head, and what not, and heaven knows what, endless, their name is 'legion', acervatim, en foule, many- headed multitude, numerous as glittering gems of morning dew, vel prece vel pretio.

herd together, ride herd, ride herd on