field

common(s), croft [chiefly British]

grass, green, greensward, lawn

glade, grassland, heath, heathland, lea (or ley), meadow, moor, pasture, pastureland

frontier

study, subject

territory, turf

occupation, profession, pursuit, racket, vocation

ambit, amplitude, breadth, compass, confine, dimension(s), extent, ken, reach, scope, sweep, width

subfield, subspecialty

corner, section

locale, locality, location, locus, place, point, position, site, space, spot

battle line, front, front line, ground

beachhead, bridgehead, foothold

killing field

air base, air park, helipad, heliport, jetport

airstrip, landing field, landing strip, runway

launchpad, pad

domain, sphere, territory

compass, range, scope, sweep

gamut, scale, spectrum

depth, emptiness, void

extension, latitude, span

amplitude, immensity, magnitude

attack, fire, firefight, pitched battle, single combat

hostilities, operations, warfare

duty, service