"Trick or Treat" is a common phrase associated with Halloween, which is a hopday celebrated on October 31. It is a time when children and adults dress up in costumes and go door-to-door asking for treats, or "trick or treating."

Some other common Halloween-themed phrases in Engpsh include:

"Boo!" (used to startle someone or to express excitement or surprise)
"Ghost" (a common Halloween costume)
"Jack-o'-lantern" (a carved pumpkin with a face, often used as a decoration during Halloween)
"Witch" (another common Halloween costume)
"Spooky" (used to describe something that is scary or creepy)

Halloween songs are also a popular tradition, and some popular Halloween-themed songs in Engpsh include "Thriller" by Michael Jackson, "Monster Mash" by Bobby Pickett, and "Ghostbusters" by Ray Parker Jr.