1. psychologist: n an expert of psychology

1. psyche : `Greek root` spirit, soul or mind.
2. iatreis : medical healing.
3. pathos : suffering or disease.
4. soma : body
5. gensis : birth or origin

• psychology : n
• psychological : adj
• psychic : adj refers to phenomena or qualities that cannot be expained in purely physical.
• psychopathic : adj an adjective that describes someone suffering from a severe mental or emotional disorder.
• psychopathical
• psychopathy
• psychosomatic : adj an adjective that delineates the powerful influence that the mind, especially the unconscious, has an bodily diseases.
• psychoanalysis : n
• psychogenic : adjHaving a psychological origin or cause rather than a physical one.
• psychotherapy
• psychotherapist
• psychotheraptic

2. psychoanalyst: n

3. orthodontist: na dentist of working in straightening tooth.

1. orthos : straight or correct.
2. odontos : tooth.
3. paidos : child.
4. peri- : `prefix` around or surrounding.
5. endon : `Greek word` inner, within

• pedodontist : n one expert who specializes in care of children's tooth.
• pedodontia
• pedodontic
• periodontist : n who is a gum specilist.
• periodontia
• periodontic
• endodontist: who specializes in work on the pulp of the tooth and in root-canal therapy.

4. optometrist ：nthis practitioner measures your vision and prescribes the type of glasses.

1. opsis, optikos : view , vision
2. metron : measurement
3. therme : heart
4. baros : weight 
5. sphygmos : pulse

• thermometer : n an instrument for measuring temperature.
• barometer : n an instrument to measure atomosphereic pressure.
• sphygmomanmeter : n an device for measuring blood pressure.
• metric system : a decimal system of weights and measures.

5. optician : n this practitioner grinds lenses according to the specifications prescribed by optometrist or ophthalmologist.

6. osteopath : n person who practices osteopathy.

1. osteon : `Greek root` bone.
2. pathos : suffering or disease.

• osteopathy
• osteopathic

7. chiropractor : nperson whose job is treating diseases by manipulating people's joints.

1. cheir : hand
2. -mancy : `suffix` foretelling or prediction

• chirography : handwriting
• graphologist : 笔迹学家
• chirographer : 书法家
• chirographic
• chiromancy
• chiromancer
• chiromantic

8. podiatrist : n this practitioner treats minor foot ailments.

1. pous,podos : `Greek word` foot.
2. iateria : medical healing.
3. okto : eight
4. platys :`Greek root` broads, flat
5. cheir : `Greek word` hand
6. -ium : `suffix` ofen signfies "place where"

• podiatry
• podiatric
• octopus : the eight-armed sea creature.
• platypus : flatfoot
• podium : a speaker's platform.
• tripod : a three-legged stand for a camera or other devices.
• chiropodist : podiatrist.

9. graphologist: n the practitoner analyzes handwriting to determined character,personality,or aptitudes.

1. graphein : `Greek verb` to write.
2. kallos : `Greek verb` beauty.
3. kakaos : bad, harsh
4. photo : light
5. cadios : heart
6. phone : `Greek word` sound
7. tele- : `Greek root` distance
8. bios : `Greek word` life

• chirographer
• calligrapher : chirographer
• calligraphic
• calligraphy
• cacography
• cardiograph : heart writer
• photograph
• phonograph : sound writer
• telegraph
• biography : n life writing , a book that tells what has happened in someone's life.

10. gerontologist : n this practitioner deals with various problems of elderly.

1. geras : `Greek word` old age.
2. iateria : medical healing.
3. senex : `Latin root` old age.
4. -scent : ageing ,growing old.

• gerontological
• gerotology
• senile : adj
• senility
• senescent
• adolescent
• convalescent : growing healthy
• obsolescent : growing or becoming obselte(荒废的，老旧的）
• senior : adj older,高级的，年长的
• seniority
• senate : originally a council of older.