Dedication: 3/15/05

ausculto (listen to): see auris/clueo.
auster: south wind

Anzac, aurora australis, Auster, austral, Australia, Australian, Australoid, Australopithecus

N.B. Austria is not derived from auster; it is Germanic.
autumnus: harvest, autumn

autumn, autumnal, autumnal equinox, autumny

auxilium: see augeo
avena: oats

avenaceous, aveniform

aveo: be eager; avidus: eager; avaritia: greed

avarice, avaricious, avariciously, Ave, Ave Maria, avid, avidity, avidly

avis: bird

augur, augury, auspicate, auspices, auspicious, auspiciously, avian, aviarist, aviary, aviate, aviation, aviator, aviatrix, avicide, avicolous, aviculture, aviculturist, avifauna, avine, avionics, aviophobia, Avis, exaugural, facilis descensus Averno, inaugural, inaugurate, inauguration, inaugurator, inauspicious, inauspiciously, ocarina, ostrich, postinauguration, preinauguration, proavis, rara avis

Augur from augeo according to W3.

avus: grandfather; avunculus: uncle

atavic, atavism, atavistic, avuncular, avuncuarism, avuncularity, avuncuarly, avunculate, granduncle, great-uncle, uncle, Uncle Tom

axilla (armpit): see ala
axis: pole

abaxial, axial, axis, coaxial, epaxial, monaxial, monaxile, monaxon, monoaxal, orthaxial, paraxial, postaxial, subaxial, triaxial

B
baca: berry

baccalaureate, baccate, bacciferous, bacciform, baccivorous, bagasse, bagatelle, bayberry, postbaccalaureate

Both ODEE and OED reject bachelor as derivative of baca and say origin obscure.
baia: bay (from Isidore)

bay (water)

baiulus: carrier

bail (set free from custody), bailiff, bailiwick, bailment

balbus: stammering

balbutient, balbuties, boob (person), booby, booby hatch, booby prize, booby trap

AHD says booby from balbus; OED asserts no connection.
balneum: bath

bagnio, balneal, balneation, balenological, balneologist, balneology, balneotherapy

balteus: belt, girdle

belt, belting, belt line

barba: beard

barb, Barbados, barbate, barbative, barbed, barbel, barbellate, barber, barbershop, barbet, barbicel, barbule, rebarbative

N.B. barbarian is derived from barbaroV, which is unrelated to barba.
Barca: Carthaginian family

Barcelona