As a Noun:
1. A knot with two loops and two loose ends that is used in tying shoelaces and ribbons. English = bow.
2. A man's tie in the form of a bow, worn especially for formal occasions. English = bow tie.
3. An occasion at which people wear smart clothes and behave carefully rather than in a casual way. English = formal.
As a Verb or Adjective:
1. To wear a bow tie.
2. Of an occasion, for example a dinner or a dance, at which people wear smart clothes. English = (be) formal.
Note:
1. The sign means any kind of bow. It means "bow-tie" if made in front of the neck, but it can be placed elsewhere on the body, e.g., on the head for "hair bow" or on the torso for any other kind of bow.