博士(はかせ)

はかせ
noun
doctor (PhD), expert
academiccolloquial
1. doctor, PhD holder
A person who has received a doctoral degree; an academic title.
He has a PhD in engineering.
博士の学位 = doctoral degree
I completed my doctoral program.
2. expert, specialist
A person with extensive knowledge in a particular field; often used colloquially or in nicknames.
My child is called a dinosaur expert.
Colloquial use for someone very knowledgeable
あの子(こ)は虫(むし)博士(はかせ)だ。
That kid is a bug expert.
Colloquial: ~博士 = expert in ~
Since he knows everything, everyone calls him 'the professor.'

Usage: 博士(はかせ) can refer to (1) an academic doctoral degree holder, or (2) colloquially, an expert in something. The reading はくし is also used in formal/academic contexts.

Common patterns

RELATED WORDS (academic degrees):

Note: 博士(はくし) is the official reading for the academic degree. 博士(はかせ) is the everyday reading, used for an expert or a "professor" figure and in titles like 「〜博士(はかせ)」.