(Greek: a suffix; meaning, specialist in, practitioner of)

academician (s) (adjective), academicians (pl)
A member of an academy or society concerned with the arts or sciences: The academicians and researchers have been entering their essays in the noted scientific publications for all the universities.
acoustician (s) (noun), acousticians (pl)
An expert who knows how to deal with the properties of sound: One occupation of an acoustician is someone who fits hard-of-hearing people with hearing aids.

After her university training, Alice was able to get a job working for a hearing aid company, working as an acoustician who was developing more efficient hearing devices.

aesthetician, esthetician (s) (noun); aestheticians; estheticians (pl)
1. A critic concerned with the theory of beauty and the fine arts: Professor Tweedie was an aesthetician and so he was able to teach a theory course about the fine arts.
2. A person who specializes in beauty treatments for clients desiring to enhance their physical appearance: Alexandria's cousin, Cathy, completed her training and is now a licensed aesthetician at an important salon in the city.
agrotechnician (s) (noun), agrotechnicians (pl)
A specialist in the science and technology of agriculture: As an agrotechnician, Mr. Weed taught classes in farm production and the machinery needed for efficient production in addition to other related areas. .
Someone who is skilled in navigating the arctic regions.
audiometrician (s) (noun), audiometricians (pl)
A technician specializing in the measurement of a hearing ability (audiometry); audiometrist: An audiometrician is an individual trained to measure an auditory threshold, and, usually, to carry out a wide variety of other audiological investigations.
A health practitioner specializing in bariatrics.
beautician (s) (noun), beauticians (pl)
1. Someone who specializes in the science of biometry, or biometrics, which is the study biostatistics including the calculation of the probable duration of human life.
2. A person who uses statistical techniques to analyze biological data.
cosmetician (s) (noun), cosmeticians (pl)
1. Someone who makes, or sells, cosmetics; or who applies them professionally.
2. A person who works in a beauty parlor.
cybernetician, cyberneticist (s) (noun), cyberneticians, cyberneticists (pl)
A specialist in the duplication or imitation of biological control methods that use technology which is similar to the human nervous system and electronic machines: Donald is one of many cyberneticians who are experts in the science of communications and automatic control elements in both machines and living things.
1. A person who diagnoses, especially a physician specializing in medical diagnostics.
2. An expert in making diagnoses; especially, a medical doctor.
3. Someone with special skills in identifying the cause or nature of a problem even in areas other than medical.
A guess of diagnosticians.