Wall-less Design - A battery design where the structural support for the cells is formed by an open plastic framework.
Power source (safety) - Power source for loads defined as critical by applicable safety regulations. This supply must not be affected by a mains failure and is generally separate from other supplies.
Fuse - Device used for cutting off an electrical current in the event of an abusive condition.
Polarity - In electricity, the condition of being positive or negative.
Load (linear) - Load for which voltage form and current form are similar. Voltage and current are related by Ohm's law U(t) = Z x I(t).
Bypass (manual) - Manually-operated switch used to supply the load via direct connection to utility power during servicing of the UPS system.
UL - Underwriters Laboratories (UL) is a non-governmental, non-profit certification organization in the United States in which not only government authorities are represented, but also consumer groups, "export" services, research, etc. Following certification, a product may bear the UL label.