fingertip
n
1 extreme end of a finger 指端; 指尖.
2 (idm 习语) have sth at one´s `fingertips be completely familiar with sth 对某事物了如指掌. to one´s `fingertips in every way; completely; through and through 各方面; 完全; 彻底
She´s an artist to her fingertips. 她是真正的艺术家.