crest vs hobby horse

crest

noun
  • A tuft, or other natural ornament, growing on an animal's head, for example the comb of a cockerel, the swelling on the head of a snake, the lengthened feathers of the crown or nape of bird, etc. 

  • The plume of feathers, or other decoration, worn on or displayed on a helmet; the distinctive ornament of a helmet. 

  • The upper curve of a horse's neck. 

  • The ridge or top of a wave. 

  • The ornamental finishing which surmounts the ridge of a roof, canopy, etc. 

  • The top line of a slope or embankment. 

  • A ridge along the surface of a bone. 

  • A design or logo, especially one of an institution, sports club, association or high-class family. 

  • Any of several birds in the family Regulidae, including the goldcrests and firecrests. 

  • The summit of a hill or mountain ridge. 

  • The helm or head, as typical of a high spirit; pride; courage. 

  • A bearing worn, not upon the shield, but usually on a helmet above it, sometimes (as for clerics) separately above the shield or separately as a mark for plate, in letterheads, and the like. 

verb
  • Particularly with reference to waves, to reach a peak. 

  • To mark with lines or streaks like waving plumes. 

  • To reach the crest of (a hill or mountain) 

  • To furnish with, or surmount as, a crest; to serve as a crest for. 

hobby horse

noun
  • A child's toy consisting of a (usually wooden or cloth) horse's head mounted on a stick. 

  • A topic about which someone loves to talk at great length. 

  • The Irish hobby, an extinct breed of horse. 

  • A puppet-like costume used in some traditional dances and festivals that gives its wearer the appearance of a man on horseback. 

  • An early bicycle with no pedals or brakes; a draisienne. 

How often have the words crest and hobby horse occurred in a corpus of books? (source: Google Ngram Viewer )