specializes
v.v. to focus on one specific activity, subject, or job. When you do this, you become an expert in that one area instead of doing many different things.
v. to concentrate one's efforts or interests on a particular area of study, business, or activity. Often implies a high degree of expertise or a narrow professional focus.
The local bakery specializes in sourdough bread.
Our law firm specializes in intellectual property cases for small technology startups.
As the market became more competitive, the company decided it specializes in high-end medical equipment rather than general hospital supplies to maintain its profit margins.
The verb is intransitive and almost always takes the preposition 'in' followed by a noun or gerund.
The doctor specializes on heart surgery.The doctor specializes in heart surgery.The verb 'specialize' takes the preposition 'in', not 'on'.