Headers are wooden reinforcements for the placement of doors and windows.

a reference to the collection of the To:, From: and Subject: fields at the start of an email message or newsgroup post; sometimes not all of the headers are visible in your software or reader

Headers are the part of an email that most people do not see. Headers contain not only the "Subject:" line, but a complete list of the path that the email took along various machines o [..]

Double wood pieces supporting joists in a floor or double wood members placed on edge over windows and doors to transfer the roof and floor weight to the studs.

Headers

System that routes exhaust from the engine.

Constructed from steel tubing, headers provide a smooth and efficient exhaust flow path from the exhaust port to the exhaust system. Headers are frequently used in performance engine applications and [..]