The act of retrieving existing data from the memory is called

Retrieving existing data from memory is called reading, expressed as read, read out or read from.

Read-out is one accepted phrase for the same retrieval action.

Read from likewise names fetching data from a location.

The plain term read denotes the identical operation.

Reading is non destructive, leaving the stored contents unchanged.

The opposite action, placing new data into memory, is called writing.