shade = ظِلّ

ظِلّ (zill) is shade. The other well known word for shade in Arabic is فَيْء (fay’). There are a number of opinions regarding the relationship between these two words: (i) they are synonymous; (ii) shade from the morning to midday (when the sun begins to decline) is called ظِلّ , and after that it’s called فَيْء ; (iii) related to the previous opinion, shade which the sun has not removed is called ظِلّ , whilst shade which used to be sunlit is called فَيْء , which is why the shade or Paradise is referred to as ظِلّ rather than فَيْء , as it is perpetual.