noun
BAD : I sat down in the shadow of a huge eucalyptus tree.
GOOD : I sat down in the shade of a huge eucalyptus tree.
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shade = sheltered from the sun: 'It's too hot here. Let's go and find some shade.' 'The branches provided plenty of shade.'
shadow = a dark shape that you see on a wall or surface when a light shines behind someone or something: 'The setting sun cast long shadows down the beach.'