noun

• (painting, photography) An area or a spot in a drawing, painting, or photograph that is strongly illuminated.
  "The image blurred into the highlight, like something familiar seen beneath disturbed though clear water; he looked at the familiar image with a kind of quiet horror and despair, at a face suddenly older in sin than he would ever be, a face more blurred than sweet, at eyes more secret than soft."
• (figurative) An especially significant or interesting detail or event or period of time.
  "Meeting my future wife was the highlight of my trip to Spain."
• (cosmetics) A strand or spot of hair dyed a different color than the rest.

verb

• (transitive) To make prominent; emphasize.
  "The Guardian has spoken to dozens of Europeans who have left, or are planning to leave. Their stories highlight surprising new migration routes – from Lisbon to Luanda, Dublin to Perth, Barcelona to Buenos Aires – as well as more traditional migration patterns."
• (transitive) To be a highlight of.
• (transitive) To mark (important passages of text), e.g. with a fluorescent marker pen or in a wordprocessor, as a means of memory retention or for later reference.
• (transitive) To dye (part of the hair) a different color than the rest.