ADJECTIVE (3)

1. of or relating to or toward the cheek;

2. lying within the mouth;
- Example: "a buccal gland"

3. oriented toward the inside of the cheek;
- Example: "the buccal aspect of the gum"

The Collaborative International Dictionary of English v.0.48:

Buccal \Buc"cal\, a. [L. bucca cheek: cf. F. buccal.] (Anat.)
   Of or pertaining to the mouth or cheeks.
   [1913 Webster]

WordNet (r) 3.0 (2006):

buccal
    adj 1: of or relating to or toward the cheek
    2: lying within the mouth; "a buccal gland"
    3: oriented toward the inside of the cheek; "the buccal aspect
       of the gum"