odont/o-

ocul/o-

eye - optical, pertaining to the eye

olfact- 

 smell - olfactory nerves

onco- 

-oma

oo- 

egg - oocyte, precursor of female gamete

oste/o- 

bone - osteodermia, bony formations in the skin

-ostomy

cut into to form an opening – colostomy, cut an opening in the large intestine

ot/o- 

ov-, ovi- 

oxy- 

oxygen - oxygenation, the saturation of a substance with oxygen

pan-

all, universal – panacea, a cure all

-pathy

pent-

pep-, peps-

digest -  pepsin, a digestive enzyme of the stomach

peri-

around – perianal, situated around the anus

phago -

-phil, -philo

like, love-  hydrophilic, water-attracting molecules

phleb-

vein - phlebitis, inflammation of the veins

-phobia

fear – acrophobia, fear of heights

pia 

tender - pia mater, delicate membrane around the brain

 and spinal cord

pili 

pin-, pino-

-plasty 

-plegia

paralysis - paraplegia, paralysis of the lower half of the body

plex-, plexus

pneumo-

poly-

multiple - polymorphism, multiple forms

post-

after, behind - posterior, places behind

pre-, pro-

before, ahead of - prenatal, before birth

procto-

rectum, anus - proctoscope, an instrument for examining the rectum

psuedo-

quad-, quadr-

re-

back, again- reinfect

rect-

ren-

retin, retic-

rectro-

- backward, behind - retrogression, to move backward in development

ruga-

fold, wrinkle - rugae, the folds of the stomach

rhin/o-

nose - rhinitis, inflammation of the nose