Enter a clue or pattern or both:
The Clue
They often begin with colons (9 letter answer)
The Answer
EMOTICONS
Tags
Notes
The answer EMOTICONS is so rare that it appears less than once every 2500 puzzles.
Related Clues
They may have smiles and frowns
Definition
EMOTICON as a noun:
1. a representation of a facial expression (as a smile or frown) created by typing a sequence of characters in sending email; ":-( and :-) are emoticons"