[1] : The Collaborative International Dictionary of English v.0.48

sunday \sun"day\, n. as. sunnandaeg; sunne, gen. sunnan, the
   sun + daeg day; akin to d. zondag, g. sonntag; -- so called
   because this day was anciently dedicated to the sun, or to
   its worship. see sun, and day.
   the first day of the week, -- consecrated among christians to
   rest from secular employments, and to religious worship; the
   christian sabbath; the lord's day.
   1913 webster

   advent sunday, low sunday, passion sunday, etc. see
      under advent, low, etc.
      1913 webster

   syn: see sabbath.
        1913 webster
see also:
sun day advent sunday low sunday passion sunday advent 
low sabbath 

[2] : The Collaborative International Dictionary of English v.0.48

sunday \sun"day\, a.
   belonging to the christian sabbath.
   1913 webster

   sunday letter. see dominical letter, under dominical.
      

   sunday school. see under school.
      1913 webster
see also:
sunday letter dominical letter dominical sunday school school 

[3] : WordNet (r) 2.0

sunday
     n : first day of the week; observed as a day of rest and worship
         by most christians syn: lord's day, dominicus, sun
     v : spend sunday; "we sundayed in the country"
see also:
lord's day dominicus sun 

[4] : Moby Thesaurus II by Grady Ward, 1.0

19 moby thesaurus words for "sunday":
   christmas, first day, sabbath, church calendar, day of rest,
   dies non, ecclesiastical calendar, fast, feast, go on furlough,
   go on leave, holiday, holy day, holytide, make holiday,
   take a holiday, take leave, vacation, weekend

[5] : Bouvier's Law Dictionary, Revised 6th Ed (1856)

sunday. the first day of the week. 
     2. in some of the new england states it begins at sun setting on 
saturday, and ends at the same time the next day. but in other parts of the 
united states, it generally commences at twelve o'clock on the night between 
saturday and sunday, and ends in twenty-four hours thereafter. 6, gill.  
john. 268; and vide bac. ab. heresy, c. d; id. sheriff, n 4; 1 salk. 78; 1 
sell. pr. 12; hamm. n. p. 140. the sabbath, the lord's day, and sunday, all 
mean the same thing. 6 gill.  john. 268; see 6 watts, 231; 3 watts, 56, 59. 
     2. in some states, owing to statutory provisions, contracts made on 
sunday are void; 6 watts, r. 231; leigh, n. p. 14; 1 p. a. browne, 171; 5 b. 
 c. 406; 4 bing. 84; but in general they are binding, although made on that 
day, if good in other respects. 1 crompt.  jervis, 130; 3 law intell. 210; 
chit. on bills, 59; wright's r. 764;,10 mass. 312 1 cowen, r. 76, n.; cowp. 
640; 1 bl. rep. 499; 1 str. 702; see 8 cowen, r. 27; 6 penn. st. r. 417, 
420. 
     4. sundays are computed in the time allowed for the performance of an 
act, but if the last day happen to be a sunday, it is to be excluded, and 
the act must in general be performed on saturday; 3 penna. r. 201; 3 chit. 
pr. 110; promissory notes and bills of exchange, when they fall due on 
sunday, are generally paid on saturday. see, as to the origin of keeping 
sunday as a holiday, neale's f.  f. index, lord's day; story on pr. notes, 
sec. 220; story on bills, sec. 233; 2 hill's n. y. rep. 587; 2 applet. r. 
264. 

Sunday >> S Words
Sunday, definition of term: Sunday
sunday_pag1.html

Trinity Sunday >> T Words
Trinity Sunday, definition of term: Trinity Sunday
trinity+sunday_pag1.html

Passion Sunday >> P Words
Passion Sunday, definition of term: Passion Sunday
passion+sunday_pag1.html

Palm Sunday >> P Words
Palm Sunday, definition of term: Palm Sunday
palm+sunday_pag1.html

Low Sunday >> L Words
Low Sunday, definition of term: Low Sunday
low+sunday_pag1.html