Meaning

• To enlarge; to make bigger.

  "The eye doctor put drops in my eye to dilate the pupil so he could see the nerve better."

• To become wider or larger; to expand.

  "His heart dilates and glories in his strength."

• To speak largely and copiously; to dwell in narration; to enlarge; with "on" or "upon".

• To use a dilator to widen (something, such as a vagina).

• (dismissal, 4chan) Expression of anger and contempt, specifically at transgender women.