1. By means of heat from the interior of the earth

See also: geothermal

• big science
• big shagbark
• big shellbark
• big shellbark hickory
• big shot
• Big Sioux River
• big sister
• big spender
• big stick
• Big Sur
• big time
• big toe
• big top
• big tree
• big wheel
• big-bang theory
• big-bellied
• big-boned
• big-bud hickory
• big-chested
• big-cone douglas fir
• big-cone spruce
• big-eared bat
• big-eyed scad
• big-leaf maple