Linked from
The 8 pages that link to Candela, each with the reason it gives.
SI base unitRelated: It completes the seven-unit set with the base quantity luminous intensity.
Luminous fluxRelated: The lumen is defined from candela and solid angle.
SteradianRelated: Its definition uses a specified luminous intensity per unit solid angle.
CandlepowerRelated: The candela replaced candlepower as the standardized unit.
FlashlightRelated: Candela measures how strongly a flashlight concentrates light toward a target.