Shadow

• shad‧ow
• 1

  dark shape

   [countable] the dark shape that someone or something makes on a surface when they are between that surface and the light:
• the long dark shadow of an old oak tree
• His shadow fell across the room.
• The building cast its shadow (=made a shadow) across the street.
• in the shadow of something
• It was hot, and we decided to walk in the shadow of the wall(=along the wall, where its shadow would fall).
• 2

  darkness

   [uncountable] also shadows [plural] darkness caused by something preventing light from reaching a place
• in shadow
• The room was half in shadow.
• in the shadows
• In the shadows something moved.
• 3

  bad effect/influence

   [singular] the bad effect or influence that something has, which makes other things seem less enjoyable, attractive, or impressive
• in/under the shadow of something
• For years, people had been living under the shadow of communism.
• cast a shadow over/on something (=make something seem less enjoyable, attractive, or impressive)
• The events of September 11th cast a shadow over the celebrations.
• 4

   without/beyond a shadow of a doubt

  used to say that something is definitely true:
• Without a shadow of a doubt, he's the most talented player we have.
• 5

   in somebody's shadow

  if you are in someone's shadow, they are much more famous and successful than you are:
• Kate grew up in the shadow of her film star sister.
• 6

   be a shadow of your former self

  to be weaker, less powerful, or worse than you were before:
• Lennox seemed like a shadow of his former self.
• 7

   shadows under your eyes

  small dark areas under your eyes that you have when you are very tired:
• She looked pale, with deep shadows under her eyes.
• 8

   somebody's shadow

  someone who follows someone else everywhere they go
• 9

   afraid/frightened/scared etc of your own shadow

  easily frightened or very nervous
• ➔ five o'clock shadow

WORD CHOICE: 

shadow, shadeA shadow is a dark shape made by something that blocks the sun or a light• She saw his shadow on the wall.Shadow is an area of darkness made like this• The side of the valley was in shadow.Shade is a cool dark area where the sun does not reach, made by the shadow of something such as a tree or wall• Let's eat our lunch in the shade.• He sat under the shade of a tree.

Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary.