fin‧ger‧tip /ˈfɪŋɡəˌtɪp $ -ɡər-/ noun [countable]

1. the end of your finger that is furthest away from your hand:
She touched his cheek gently with her fingertips.

2. have something at your/their etc fingertips to have knowledge or information ready and available to use very easily:
We have all the facts and figures at our fingertips.

3. to his/her fingertips British English in all ways; completely:
She’s British to her fingertips.

[TahlilGaran] Dictionary of Contemporary English ▲

fingertip
See: AT ONE'S FINGERTIPS.

[TahlilGaran] English Idioms Dictionary ▲