frontal_sinus
1. [ noun ] (anatomy,zoology) one of a pair of cavities in the frontal bone
Related terms: sinus
Similar spelling:   frontal_gyrus
  frontal_suture
  frontstall
  front-stall
  frontal_lobe
  frontal_bone
  frontal_area
  frontal_eminence
  front_line
  frontal_cortex