British spelling: becomes aware of something; understands or comes to know something; also means to make something real or achieve it.
From Old French 'real' (actual, royal), from Latin 'realis' (relating to things). The meaning evolved from 'making real' to 'understanding' something as real.
The British spelling 'realises' vs. American 'realizes' shows how English split into regional variants after the 1700s, with British English keeping French-influenced '-ise' and American English standardizing to '-ize'.
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