grid has 5 distinct synonyms spread across 4 of its 5 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a pattern of regularly spaced horizontal and vertical lines
a system of high tension cables by which electrical power is distributed throughout a region
a perforated or corrugated metal plate used in a storage battery as a conductor and support for the active material
an electrode placed between the cathode and anode of a vacuum tube to control the flow of electrons through the tube
a cooking utensil of parallel metal bars; used to grill fish or meat
Synonyms, antonyms and the broader and narrower relations for grid come from Princeton University’s WordNet. Full sources and licences.