(verb)
to make a harsh rasping sound, often due to grinding on something, or to say something in a scratchy and unpleasant voice;
e.g. The gates grate when they swing because they have become rusted.
(verb)
to be jarring and irritating or to have such an effect;
e.g. All of their questions began to grate at her but she tried to answer then as nicely as she could.
(noun)
a frame fitted with parallel and/or crossing bars, often serving to cover something or create a barrier/partition;
e.g. The window was fitted with a grate to prevent people from breaking in.
(verb)
to furnish or fit something with a framework of parallel and/or crossing bars, usually as a covering or barrier;
e.g. They had to grate the air vent to prevent things from being sucked into it.
(noun)
a fireplace, or a gap/depression in a wall intended for a furnace or fireplace;
e.g. He lit a fire in the grate to warm up the room.
(noun)
a frame fitted with metal bars that is used with a fire, for example when cooking over a fire (to hold/place food), to hold fuel (e.g. wood), or to hold a small stove;
e.g. She placed a pot on the grate and set the water to boil.