Source : Webster's Revised Unabridged Dictionary (1913)

Grateful \Grate"ful\, a. [Grate, a. + full; cf. F. gr['e]
   thanks, good will, fr. L. gratum, neut. of gratus agreeable,
   grateful. See {Grate}, a.]
   1. Having a due sense of benefits received; kindly disposed
      toward one from whom a favor has been received; willing to
      acknowledge and repay, or give thanks for, benefits; as, a
      grateful heart.

            A grateful mind By owing, owes not, but still pays.
                                                  --Milton.

   2. Affording pleasure; pleasing to the senses; gratifying;
      delicious; as, a grateful present; food grateful to the
      palate; grateful sleep.

            Now golden fruits on loaded branches shine, And
            grateful clusters swell.              --Pope.

   Syn: Thankful; pleasing; acceptable; gratifying; agreeable;
        welcome; delightful; delicious. -- {Grate"ful*ly}, adv.
        -- {Grate"ful*ness}, n.

Source : WordNet®

gratefulness
     n : warm friendly feelings of gratitude [syn: {thankfulness}, {appreciativeness}]