1. a bog, usually a sphagnum bog, frequently with tussocks of deep accumulations of organic material, growing in wet, poorly drained boreal areas, often areas of permafrost 2. a tract of partly forested peatland supporting mosses (particularly sphagnum), shrubby plants (particularly Ericaceae) and scattered Picea and Larix trees 3. the peat itself on such a tractThis definition last updated 07/20/2008