marl

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A crumbly mixture of clays, calcium and magnesium carbonates, and remnants of shells that is sometimes found under desert sands and used as fertilizer for lime-deficient soils.
2. v. To fertilize with such a mixture.

Century Dictionary and Cyclopedia

1. n. A mixture of clay with carbonate of lime, the latter being present in considerable quantity, forming a mass which is not consolidated, but falls to pieces readily on exposure to the air. The word marl, however, is used so vaguely as to be often ambiguous; and in England some substances are thus designated in which there is no lime. Marl is a valuable fertilizing material for different kinds of soil, according to its composition. In New Jersey the mixtures of greensand with clay much used as fertilizers are commonly called marls. or greensand-marls, and many varieties thus designated contain no more than one or two per cent, of carbonate of lime. Marls and marly soils are especially well developed in the Permian and Triassic of England and on the continent. The upper division of the Keuper in England is known as the “Red Marl Series,” and in places reaches a thickness of 3,000 feet. These marls are largely quarried at various points for making bricks. See shell-marl.
2. To overspread or manure with marl.
3. Nautical, to wind, as a rope, with marline, spun-yarn, twine, or other small stuff, every turn being secured by a sort of hitch: a common method of fastening strips of canvas called parceling, to prevent chafing.
4. To ravel, as silk.
5. n. The fiber of those peacock-feathers which have the webs long and decomposed, so that the barbs stand apart, as if raveled: used for making artificial flies.
6. To wonder; marvel.
7. n. Marble.
8. n. A marble (plaything).
9. See the quotation.

Wiktionary

1. n. A mixed earthy substance, consisting of carbonate of lime, clay, and possibly sand, in very variable proportions, and accordingly designated as calcareous, clayey, or sandy.
2. v. To cover, as part of a rope, with marline, marking a peculiar hitch at each turn to prevent unwinding.

GNU Webster's 1913

1. v. (Naut.) To cover, as part of a rope, with marline, marking a pecular hitch at each turn to prevent unwinding.
2. n. A mixed earthy substance, consisting of carbonate of lime, clay, and sand, in very variable proportions, and accordingly designated as calcareous, clayey, or sandy. See greensand.
3. v. To overspread or manure with marl.

WordNet 3.0

1. n. a loose and crumbling earthy deposit consisting mainly of calcite or dolomite; used as a fertilizer for soils deficient in lime