SAFETY FOLD ENVELOPE - An open side, center seam envelope with a large wallet flap and a high throat designed to fold over with the flap to increase the security of the contents.

SEAL GUM - Any adhesive applied to the seal flap of the envelope in order to achieve a seal. See closures.

SEAL FLAP - The flap that folds down over the envelopes opening in order to seal it.

SEAM - The back of an envelope where it is glued together. Center Seam - on an Open End Catalog or Booklet where the seam runs down the middle of the back; Side Seam - on an Open End Catalog or Booklet where the seam is on the side of the envelope.

SHOULDER - The top edge of the side flaps at the envelope opening.

SIDE FLAPS - Fold in from the sides to form the sides of the envelope.

SIDE SEAM - A seam that runs perpendicular to the envelope opening.

SIDE SEAM INSIDE - The term applied to the side seam when it folds UNDER the bottom flap.

SIDE SEAM OUTSIDE - The term applied to the side seam when it folds OVER the bottom flap.

SIZE - The measurement in length and width of an envelope or window.

SPECIAL - A very general term used to describe any envelope that is not of a standard size, window position, or paper grade.

SPLIT SEAL GUM - Broken gum pattern on seal flap to prevent “tabbing.” Gum is broken where flap covers envelope seams; prevents flap from sticking to the back panel during storage in humid conditions.

STAMP READY - Seal gum is stopped 2" from the postal stamp side of the envelope. This is done to keep tacking from occurring when a postal stamp is applied.

STRAIGHT GRAIN CUT - Envelope is cut so that the paper grain runs parallel to the side fold. Envelope is easier to fold and has less tendency to curl or warp with the straight grain cut.