Shade, shadow, umbrage, umbra, penumbra, adumbration can mean the comparative darkness caused by something which intercepts rays of light.
Shade carries no implication of a darkness that has a particular form or definite limit but the term often stresses protection from the glare, heat, or other effect of the light that is cut off.
Shadow usually applies to shade which preserves something of the form of the object which intercepts the light. In extended use shade implies darkness or obscurity; shadow, insubstantiality or unreality.
Umbrage (see also OFFENSE ) applies chiefly to the shade cast by heavy foliage or trees, though sometimes it refers to the mass of trees or foliage which make for heavy shade.
Its occasional extended use can draw meaning from either of these aspects and suggest, on the one hand, an indistinct indication, as if of something seen in deep shadow or, on the other, an overshadowing influence.
Umbra and penumbra are largely astronomical and optical terms.
Umbra applies to the perfect or complete shadow cast on the moon or the earth in an eclipse, and penumbra to the imperfect or partly illuminated shadow which often surrounds the umbra
Umbra rarely and penumbra often are used in extended senses, the former implying a complete overshadowing or eclipse, the latter denoting the marginal region or border between areas which are themselves clearly one thing or the other, or in which the exact differences between one thing or another are so obscure as not to be clearly discernible.
Adumbration applies to something that is so faint or obscure a figure, sketch, or outline of something which actually exists or is to come that it serves as a foreshadowing of it or a hinting at it.