-ician

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

academician
A member of an academy or society concerned with the arts or sciences.
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: "The professor 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, farm production, the machinery needed for efficient production, etc.
apician
arctician
Someone who is skilled in navigating the arctic regions.
audiometrician
1. A technician specializing in the measurement of hearing ability (audiometry).
2. A person trained to measure auditory threshold, and, usually, to carry out a wide variety of other audiological investigations.
bariatrician
A health practitioner specializing in bariatrics.
beautician (s) (noun), beauticians (pl)
biometrician
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.
clinician
cosmetician
1. Someone who makes, or sells, cosmetics; or who applies them professionally.
2. Someone who works in a beauty parlor.
cybernetician, cyberneticist (s) (noun), cyberneticians, cyberneticists (pl)
A specialist in the duplication or imitation of biological control systems that use technology which is similar to the human nervous system and electronic machines: "Cyberneticians are experts in the science of communications and automatic control elements in both machines and living things."
diagnostician
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.
diagnosticians
A guess of diagnosticians.