Adjective

(en adjective)

Making good, thorough, or careful use of resources; not consuming extra. Especially, making good use of time or energy.

* {{quote-magazine, title=A better waterworks, date=2013-06-01, volume=407, issue=8838

, page=5 (Technology Quarterly), magazine=(The Economist) citation , passage=An artificial kidney these days still means a refrigerator-sized dialysis machine. Such devices mimic

Using a particular proportion of available energy.

Causing effects; producing results.

* Wilson

The efficient cause is the working cause.

Adjective

(en adjective)

Resulting in success; assuring, or promotive of, success; accomplishing what was proposed; having the desired effect; prosperous; fortunate; happy

* {{quote-book, year=2006, author=(Edwin Black), title=Internal Combustion

, chapter=1 citation , passage=If successful , Edison and Ford—in 1914—would move society away from the ever more expensive and then universally known killing hazards of gasoline cars: […] .}}

* {{quote-magazine, date=2013-06-21, author=(Oliver Burkeman)

, volume=189, issue=2, page=27, magazine=(The Guardian Weekly) , title= The tao of tech , passage=The dirty secret of the internet is that all this distraction and interruption is immensely profitable. Web companies like to boast about […], or offering services that let you