Graph (5)
'graph' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for chart that I've seen before include "Marine map" , "Hit parade" , "Map to assist navigation by sea" , "Table or diagram" , "Visual display of information" .)
(Other definitions for grid that I've seen before include "method to find map reference" , "crossword, but no clues" , "This crossword structure" , "frame" , "Rectangular network" .)