buccal vs labial

buccal

adj
  • Of, relating to, near, involving, or supplying the cheek. 

  • Of, relating to, or lying in the mouth. 

  • Administered in the mouth, not by swallowing but by absorption through the skin of the cheek; often by placing between the top gum and the inside of the lip. 

labial

adj
  • Of or pertaining to the lips or labia. 

  • Articulated by the lips, as the consonants b, m and w. 

  • Furnished with lips. 

  • On the side facing the lips. See mesial. 

noun
  • A consonant articulated by the lips. 

  • An organ pipe having a lip that influences its sound. 

  • Any of the scales bordering the mouth opening of a reptile. 

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