Ocotillo
A spiny desert shrub with red flower clusters at the tips of its branches.

Off-highway Vehicle
(OHV) Any snowmobile, all-terrain vehicle, or motorcycle.

OHV
See Off-highway Vehicle.

Omnivore
An animal which eats a variety of plant and animal materials.

Ore
The naturally occurring material from which a mineral or minerals of economic value can be extracted at a reasonable profit.

Organic Compounds
Compounds produced in or by plants and animals and containing carbon as the essential ingredient.

ORV
Off-Road Vehicle.

Outcrop
That part of a geologic formation that appears at the surface of the Earth.

Overwinter
To go through a period of dormancy during the cold season.

Ovipositor
An egg-laying organ at the rear end of the female's abdomen.