n[C]
[Date: 1800-1900; Language: German;Origin: leitmotiv, from leiten 'to lead' + motiv 'motive' (from French motif)]
technical a musical phrase that is repeated several times during a long musical work and represents a particular character or idea
something that is seen or heard very many times and so becomes a typical feature of a place, time, or person
　Her designs in clothing became a leitmotif of the 1970s.