Source : Webster's Revised Unabridged Dictionary (1913)

Economic \E`co*nom"ic\ (?; 277), Economical \E`co*nom"ic*al\, a.
   [F. ['e]conomique, L. oeconomicus orderly, methodical, Gr. ?
   economical. See {Economy}.]
   1. Pertaining to the household; domestic. ``In this
      economical misfortune [of ill-assorted matrimony.]''
      --Milton.

   2. Relating to domestic economy, or to the management of
      household affairs.

            And doth employ her economic art And busy care, her
            household to preserve.                --Sir J.
                                                  Davies.

   3. Managing with frugality; guarding against waste or
      unnecessary expense; careful and frugal in management and
      in expenditure; -- said of character or habits.

            Just rich enough, with economic care, To save a
            pittance.                             --Harte.

   4. Managed with frugality; not marked with waste or
      extravagance; frugal; -- said of acts; saving; as, an
      economical use of money or of time.

   5. Relating to the means of living, or the resources and
      wealth of a country; relating to political economy; as,
      economic purposes; economical truths.

            These matters economical and political. --J. C.
                                                  Shairp.

            There was no economical distress in England to
            prompt the enterprises of colonization. --Palfrey.

            Economic questions, such as money, usury, taxes,
            lands, and the employment of the people. --H. C.
                                                  Baird.

   6. Regulative; relating to the adaptation of means to an end.
      --Grew.

   Note: Economical is the usual form when meaning frugal,
         saving; economic is the form commonly used when meaning
         pertaining to the management of a household, or of
         public affairs.

Source : WordNet®

economical
     adj 1: using the minimum of time or resources necessary for
            effectiveness; "an economic use of home heating oil";
            "a modern economical heating system"; "an economical
            use of her time" [syn: {economic}]
     2: of or relating to an economy, the system of production and
        management of material wealth; "economic growth"; "aspects
        of social, political, and economical life" [syn: {economic}]
     3: avoiding waste; "an economical meal"; "an economical
        shopper"; "a frugal farmer"; "a frugal lunch"; "a sparing
        father and a spending son"; "sparing in their use of heat
        and light"; "stinting in bestowing gifts"; "thrifty
        because they remember the great Depression"; "`scotch' is
        used only informally" [syn: {frugal}, {scotch}, {sparing},
         {stinting}]