Document type definition. A document type definition (DTD) is a set of markup declarations that define a document type for an SGML-family markup language (SGML, XML, HTML). A Document Type Definition (DTD) defines the legal building blocks of an XML document. It defines the document structure with a list of legal elements and attributes. A DTD can be declared inline inside an XML document, or as an external reference.
American hornbeam. The American hornbeam is a native forest understory tree in the Chicago area, making it useful for shady landscapes and naturalized or woodland gardens.New leaves emerge reddish-purple, changing to dark green, then turn yellow to orange-red in the fall, offering a kaleidoscope of color throughout the year.merican hornbeam. The American hornbeam is a native forest understory tree in the Chicago area, making it useful for shady landscapes and naturalized or woodland gardens.
Ridge Beam vs. Ridge Board. A Ridge Beam and a Ridge Board are both located at the ridge but they serve very different purposes for very different applications. A ridge beam is a structural member used to support the ends of the rafters at the ridge, transferring it's loads to posts or gable end walls. Ridge beams are required by code if the roof slope is less than 3 in 12 (IRC section R802.3).