Peat is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. Sphagnum moss, also called peat moss, is one of the most common components in peat, although many other plants can contribute. The biological features of sphagnum mosses act to create a habitat aiding peat formation, a phenomenon termed 'habitat manipulation'. Soils consisting primarily of peat are known as histosols. Peat forms in wetland conditions, where flooding or stagnant water obstructs the flow of oxygen from the atmosphere, slowing the rate of decomposition. Peat properties such as organic matter content and saturated hydraulic conductivity can exhibit high spatial heterogeneity.

पीट एक प्रकार के कोयले को कहते हैं। पीट प्राकृतिक रूप से पौधों के ऐसे पर्यावरण में सड़ने से होता है जिसमें पानी अधिक मात्रा में हो तथा ऑक्सीजन ना हो। पीट का निर्माण ऑर्गेनिक सामग्री के कार्बनन से होता है।