| A | B |
| conservation | protection of valued resources |
| energy | power supply or source |
| energy audit | a survey of energy use |
| energy efficient | using energy in an economical way |
| conservation of energy | energy remaining constant |
| conservationist | supporter of environmental conservation |
| electricity | energy by moving charged particals |
| battery | a number of connected electric cells that produce a direct current through the conversion of chemical energy into electrical energy |
| direct current | unidirectional electrical current: electrical current that flows in only one direction and has a fairly constant average value. |
| alternating current | reversing current: an electric current that regularly reverses direction |