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

grave \grave\, a. compar. graver gr=av"~er; superl.
   gravest. f., fr. l. gravis heavy; cf. it.  sp. grave
   heavy, grave. see grief.
   1. of great weight; heavy; ponderous. obs.
      1913 webster

            his shield grave and great.           --chapman.
      1913 webster

   2. of importance; momentous; weighty; influential; sedate;
      serious; -- said of character, relations, etc.; as, grave
      deportment, character, influence, etc.
      1913 webster

            most potent, grave, and reverend seigniors. --shak.
      1913 webster

            a grave and prudent law, full of moral equity.
                                                  --milton.
      1913 webster

   3. not light or gay; solemn; sober; plain; as, a grave color;
      a grave face.
      1913 webster

   4. mus.
      a not acute or sharp; low; deep; -- said of sound; as, a
          grave note or key.
          1913 webster

                the thicker the cord or string, the more grave
                is the note or tone.              --moore
                                                  encyc. of
                                                  music.
      b slow and solemn in movement.
          1913 webster

   grave accent. pron. see the note under accent, n., 2.

   syn: solemn; sober; serious; sage; staid; demure; thoughtful;
        sedate; weighty; momentous; important.

   usage: grave, sober, serious, solemn. sober supposes
          the absence of all exhilaration of spirits, and is
          opposed to gay or flighty; as, sober thought. serious
          implies considerateness or reflection, and is opposed
          to jocose or sportive; as, serious and important
          concerns. grave denotes a state of mind, appearance,
          etc., which results from the pressure of weighty
          interests, and is opposed to hilarity of feeling or
          vivacity of manner; as, a qrave remark; qrave attire.
          solemn is applied to a case in which gravity is
          carried to its highest point; as, a solemn admonition;
          a solemn promise.
          1913 webster
see also:
graver gravest. grief. grave accent accent grave 
sober serious solemn. 

[2] : WordNet (r) 2.0

grave accent
     n : a mark ` placed above a vowel to indicate pronunciation
         syn: grave
see also:
grave 

Grave Accent >> G Words
Grave Accent, definition of term: Grave Accent
grave+accent_pag1.html

Accent >> A Words
Accent, definition of term: Accent
accent_pag1.html

Grave >> G Words
Grave, definition of term: Grave
grave_pag1.html

Accent Mark >> A Words
Accent Mark, definition of term: Accent Mark
accent+mark_pag1.html

Acute Accent >> A Words
Acute Accent, definition of term: Acute Accent
acute+accent_pag1.html