Oasis
A fertile place in the desert where there is water and some vegetation.
Obsidian
Glassy dark colored volcanic rock. Usually composed of rhyolite.
Ocean
A large body of salt water that surrounds a continent. Oceans cover more than two-thirds of the Earth’s surface. (see more about oceans)
Oceanic Spreading Ridge
An oceanic spreading ridge is the fracture zone along the ocean bottom where molten mantle material comes to the surface, thus creating new crust. This fracture can be seen beneath the ocean as a line of ridges that form as molten rock reaches the ocean bottom and solidifies.
Oceanic Trench
An oceanic trench is a linear depression of the sea floor caused by the subduction of one plate under another.
Offal
Edible organs of an animal.
Off-Set Jaws (hunting)
The type of jaws on a leg-hold trap that, when closed, retain a gap of approximately 1/8 to 1/4 inch.
Ogive
Bands of light and dark material on a glacier.
Open Wound
An injury that is exposed due to broken skin. An open wound is at high risk for infection.
Orienteering
Using a map and compass in the field to determine your route of travel.
Outhaul (boating)
Rope used to stretch a sail tight along the boom.
Outside Spread (hunting)
The distance between the two widest points on an animal’s antlers.
Overcast
Sky condition when greater than 9/10 of the sky is covered by clouds.
Oxbow Lake
An oxbow lake is a stagnant lake that is formed alongside a winding river when the river changes path because of soil erosion, leaving an abandoned stream channel, cut off from the rest of the river.
Ozone Layer
Atmospheric concentration of ozone found at an altitude of 10 to 50 kilometers above the Earth’s surface. This layer is important to life on the Earth because ozone absorbs harmful ultraviolet radiation.