The word "specialise" is the British English spelling of "specialize" (US spelling).
The artist specializes in art.
Samantha can specialize phones by plugging them into her computer and adding a few electronic apps.
After studying cooking for several years, her love of chocolate made her decide to specialize in desserts.
Did you hear that the new medical school graduate, sitting right over there, is going to specialize in neurosurgery?
speculation are rife that America is going to attack Pakistan
Many people specialize in many different jobs.
Puritan women specialized in cooking and cleaning.
the geriatrics treatment seems to help the elderly
I own a company that creates outdoor living spaces. I specialize in architectural outdoor landscape and design.
They can be called "janitors" or "housekeepers" or if they specialize in window cleaning, then "window cleaners" ! Example Sentence: "Echelon Towers Voorhees is looking to hire a janitor."
they specialize in technology