quadrat

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Printing A piece of type metal lower than the raised typeface, used for filling spaces and blank lines.
• noun Any of a group of small, usually rectangular plots of land used for sampling the occurrence of species or of archaeological artifacts.

from The Century Dictionary.

• See quadrate.
• noun In printing, a blank type for the larger blank spaces in or at the end of printed lines, cast lower in height, so that it shall not be inked or impressed: made in four forms for all text type—en, em, two-em, three-em. Usually abbreviated to quad.
• noun The low quadrat, for letterpress work, is about three fourths of an inch high: the high quadrat, for stereotype work, is about ten twelfths of an inch high.
• noun An instrument furnished with sights, a plummet, and an index, and used for measuring altitudes, but superseded by more perfect instruments in modern use. Also called geometrical square, and line of shadows.
• noun A series or set of four.
• noun In experimental agriculture, a square area of convenient size laid off for the purpose of accurate planting.
• noun In phytogeography, a similar square laid off for close study of the relative abundance of species or of other questions.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Print.) A block of type metal lower than the letters, -- used in spacing and in blank lines.
• noun An old instrument used for taking altitudes; -- called also geometrical square, and line of shadows.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun sciences A rectangular area of land, marked for studying its plants, animals, soil, natural processes, etc.
• noun obsolete A quad; a blank metal block used to fill space in lines of type.