Laminated veneer lumber (LVL) is an engineered wood product that uses multiple layers of thin wood assembled with adhesives. It offers several advantages over typical milled lumber: it is stronger, straighter, and more uniform. It is much less likely than conventional lumber to warp, twist, bow, or shrink due to its composite nature. Made in a factory under controlled specifications, LVL products allow users to reduce the onsite labor. They are typically used for headers, beams, rimboard, and edge-forming material.
It is similar in appearance to plywood without crossbands, and is typically rated by the manufacturer for elastic modulus and allowable bending stress. Common elastic moduli are 1,800,000 psi (12,400 MPa); 1,900,000 psi (13,100 MPa); and 2,000,000 psi (14,000 MPa); and common allowable bending stress values are 2,800 psi (19 MPa); and 3,000 psi (21 MPa).
A comparable material is parallel strand lumber (PSL), or laminated strand lumber (LSL) which is used in the same applications. Rather than being manufactured from full, parallel veneers, PSL uses veneers with more defects in a more random-looking pattern, and LSL uses smaller veneers, and so is similar to oriented strand board (OSB) in appearance. All belong to the general category of Structural Composite Lumber.
Source: Wikipedia