Definify.com
Webster 1913 Edition
Sake
Sake
(sāk)
, Noun.
 [OE. 
sake 
cause, also, lawsuit, fault, AS. sacu 
strife, a cause or suit at law; akin to D. zaak 
cause, thing, affair, G. sache 
thing, cause in law, OHG. sahha
, Icel. sök
, Sw. sak
, Dan. sag
, Goth. sakjō 
strife, AS. sacan 
to contend, strive, Goth. sakam
, Icel. saka 
to contend, strive, blame, OHG. sahhan
, MHG. sachen
, to contend, strive, defend one’s right, accuse, charge in a lawsuit, and also to E. seek
. Cf. Seek
.] Final cause; end; purpose of obtaining; cause; motive; reason; interest; concern; account; regard or respect; – used chiefly in such phrases as, for the sake of, for his sake, for man's sake, for mercy's sake, and the like; 
as, to commit crime for the 
. sake 
of gain; to go abroad for the sake 
of one's healthMoved with wrath and shame and ladies' 
sake
. Spenser.
I will not again curse the ground any more for man's 
sake
. Gen. viii. 21.
Will he draw out,
For anger's
For anger's
sake
, finite to infinite? Milton.
Knowledge is for the 
sake 
of man, and not man for the sake 
of knowledge. Sir W. Hamilton.
☞ The -s of the possessive case preceding sake is sometimes omitted for euphony; as, for goodness sake. “For conscience sake.” 
1 Cor. x. 28. 
The plural sakes is often used with a possessive plural. “For both our sakes.” Shak.
 Webster 1828 Edition
Sake
SAKE
,Noun.
  1.
  Final cause; end; purpose; or rather the purpose of obtaining.  I open a window for the sake of air, that is, to obtain it, for the purpose of obtaining air.  I read for the sake of instruction, that is, to obtain it.  Sake then signifies primarily effort to obtain, and secondarily purpose of obtaining.  The hero fights for the sake of glory; men labor for the sake of subsistence or wealth.2.
  Account; regard to any person or thing. I will not again curse the ground any more for man's sake.  Gen. 8.
Save me for thy mercies' sake.  Ps. 6.