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The terms in the above image are typically used to describe the various parts of a metal plate connected wood truss. The truss profile, span, heel height, overall height, overhang and web configuration depend on specific design conditions and will vary by application.

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Here are some definitions of common roof truss terms:

• Bottom Cord - The main member of a truss running along its lower side between supports and usually carrying combined tension and bending.
• Cantilever - The condition where top and bottom chords extend beyond a support with no bearing at the extended portion.
• Clear Span - Horizontal measurement between the inside faces of the bearing supports.
• Heel - The point on a truss at which the top and bottom chords intersect, usually occurring at support.
• Level Return - A horizontal member of the truss running from the end of the overhang back to the outside of the wall to form a soffit.
• Nominal Span - Horizontal distance between outside edges of supports.
• Overall Truss Length - The horizontal length of truss including the cantilever, but not the overhang.
• Overhang - The extension of a top or bottom chord of a truss beyond a support.
• Panel Point - A point at which one or more web members intersect the top or bottom chord.
• Panel Length - The centerline distance measured horizontally between two panel points.
• Peak - The point on a truss where the sloping top chords meet.
• Pitch - The inches, or fraction thereof, of vertical rise in 12 inches of horizontal run for inclined members. Usually expressed as 4/12, 8/12, etc.
• Purlin - Horizontal member placed between two main load carrying structural members. They can be used as spacers carrying decking or roofing materials and providing some lateral support for the main members.
• Slope - See Pitch.
• Top Chord - Main member of a truss running along its upperside supporting the decking and usually carrying combined compression and bending.
• Webs - Members that connect top and bottom chords together forming triangular openings to give truss action and usually carrying compression or tension forces.