Rashi on Exodus 3:5/רש"י על שמות ג׳:ה׳

1של means DRAW OFF and take off. It is of the same root as, (Numbers 19:5) “and the iron-head slippeth off (נשל) from the handle”; (Deuteronomy 28:40) “for thine olives shall drop off (ישל)‎”.

2אדמת קדש הוא the place IS HOLY GROUND (i. e. the masculine pronoun הוא refers to the word המקום and not to אדמת, which is feminine).