bacter- or bacterio- Denotes bacteria (bacteremia, bacteriocide, bacteriophage).

balan- or balano- [from Greek balanos acorn, glans penis] (1) pertaining to the glans penis or glans clitoridis (balanopreputial); (2) acorn, acornlike (Balanidae).

bar- or baro- or bary- [from Greek barys heavy] Weight, heaviness, pressure (barospirator, barotaxis).

bathy- (also bath- or batho-) [from Greek bathos depth] Depth, deep (bathypelagic).

batrach- [from Greek batrachos frog] Frog, toad (batrachoid, batrachophagous, batrachotoxin).

bi- or bio- [from Greek bios way of life] Life, living organisms (bioluminescence).

bi- or bis- [Latin bis twice] Twice, double (bisetose, bipedal).

bili- [from Latin bilis gall, bile] Pertaining to bile (bilirubin).

blast- or blasto- [from Greek blastos bud] Bud(ding), germ (blastema, blastocyst).

blenn- or blenno- [from Greek blennos mucus] Mucus, or pertaining to mucus (blennostatic).

blatt or blatta- [from Latin blatta nocturnal insect, especially: roach] In taxonomic names: nocturnal insect especially: roach (Blattaria).

blephar- or blepharo- (1) [from Greek blepharon eyelid] eyelid (blepharoclonus); (2) [from Greek blepharis eyelash] Eyelash, cilium (blepharoplast).

bothr- or bothro- [from Greek bothros pit, cavity] Pit, hole, trough (Bothriocephalus).

botry- or botryo- [from Greek botrys bunch of grapes] Like a bunch of grapes (botryoid).

brachi- or brachio- [from Latin brachium arm] Armlike, of or relating to an arm (brachialis).

brachy- [from Greek brachys short] Short (brachydactylous, brachydont).

brady- [from Greek bradys slow] Slow, dull (bradytelic).

branchi- or branchio- [from Greek branchia gills] Gill(s), branchiae (branchial, branchiate).

brevi- [from Latin brevis short, small, brief] Short, small, brief (brevicone).

bronch- or broncho- or bronchi- or bronchio- [from Greek bronchia bronchial tubes] Of or relating to the bronchi (bronchitis).

bry- or bryo- [from Greek bryon moss] Moss (bryophytes, bryology).

bucc- or bucco- [from Latin bucca mouth, cheek] Pertaining to the cheek or mouth (buccal).

burs- or bursa- or burso- [from Latin bursa bag, purse] Denotes bursa (bursalogy).