alternative
item or means of completing a goal if the primary item or method fails or is not available
sleeper dike
dike which does not normally face water
second opinion
opinion on a matter disputed by two or more parties
alternate route
United States special route that provides an alternate alignment for a highway
ancillary weapon
a weapon used for secondary or auxiliary purpose
backup site
alternative location where an organization can relocate following a disaster, such as fire, flood, terrorist threat or other disruptive event
fallback font
reserve typeface containing many Unicode characters that is used when a glyph for a character is not available in any of the preferred typefaces
alternate airport
airport to be used in case of emergency or as alternate landing place
emergency power system
independent backup source of electrical power that supports important electrical systems on loss of normal power supply
detour
diversion on a route
provisional ballot
ballot requiring further verification of voter's eligibility, used if eligibility cannot be established at the time the ballot is cast
safe mode
special mode of a computer operating system or application software with reduced functionality, for the purposes of diagnostics, troubleshooting or recovery
backup battery
battery that powers a system when its usual power source is unavailable
contingency plan
plan in case something unexpected occurs, which is often used for risk management
ancillary market
non-theatrical market for entertainment