Adhesive in relation to a stamp affixed to envelopes by means of gum on the reverse.However, some stamps are printed directly onto postcards, envelopes or wrappers.

-see also:
"Adhesive" is in the NAICS Code "32552"
  Adhesive Manufacturing

"Adhesive" is in the HS Code "3005.10"
  - - Adhesive dressings and other articles having an adhesive layer

"Adhesive" is in the UNSPSC Code "31201522"
  Adhesive transfer tape