An Etymological Dictionary of Astronomy and Astrophysics

In physics, capacity for doing work.

Etymology (EN): From M.Fr. energie, from L.L. energia, from Gk. energeia “force in action, activity, operation,” from energos “active, working,” from en- “in, at” + ergon “work,” from PIE base *werg- “to work” (cf. Av. varəz- “to work, do, perform, exercise;” Mod.Pers. varz-, varzidan “to labor, exercise, practise;” Arm. gorc “work;” Lith. verziu “tie, fasten, squeeze,” vargas “need, distress;” Goth. waurkjan; O.E. wyrcan “work,” wrecan “to drive, hunt, pursue”).

Etymology (PE): Kâruž, literally “work strength,” from kâr + už. The first component kâr “work,” Mid.Pers kâr, Mod./Mid.Pers. kardan “to do, to work,” Mid.Pers. kardan; O.Pers./Av. kar- “to do, make, build,” Av. kərənaoiti “he makes;” cf. Skt. kr- “to do, to make,” krnoti “he makes, he does,”
karoti “he makes, he does,” karma “act, deed;” PIE base k^wer- “to do, to make.” The second component, už, from Mid.Pers. ôž “strength” (ôžômand “strong”), Av. aogah-, aojah- “strength” (aojahvant- “strong”) Skt. ojas- “strength” (ojasvant- “strong”); L. augustus “venerable,” L.L. augmentare “to increase,” from augere
“to increase, enlarge, enrich;” Lith. augu “to grow;” Gk. auxo “increase;” Goth. aukan “to grow, increase;” O.E. eacien “to increase”); PIE *augos- “force,” *aug- “to increase.”