A specialist who is primarily concerned with a subspecialty within a larger specialty.(noun)
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Use "subspecialist" in a sentence
"Out of desperation, insomniacs may problem-solve independently, most commonly resorting to alcohol as a self medication, not understanding that there is in this country, more so than anywhere else, a certified subspecialist sleep medicine community which exists to solve exactly these problems."
"There needs to be a diagnostic formulation, and this may require further evaluation by a subspecialist such as a developmental-behavioral pediatrician, pediatric neurologist, pediatric psychologist, or child psychiatrist."
"A resident and Fellowship trained medical subspecialist knows their specialty."