Noun
the finger next to the thumb
Source: WordNetThe basis of computer work is predicated on the idea that only the brain makes decisions and only the index finger does the work. Brian Eno
Artemis Fowl grinned right back at him and pointed his index finger to the sky... from the tip of this finger sprang a small blue spark that exploded like a tiny firework. "I know magic can be stolen,” said Artemis. "Because I stole some myself. Eoin Colfer
A mutation in a DNA molecule within a chromosome of a skin cell in my index finger has no influence on heredity. Fingers are not involved, at least directly, in the propagation of the species. Carl Sagan
In my sights I carve him like a sculptor. I mold out his last look at everyone. I carry his eyes and his brain bone at every position. I know his male sex and I do march over him with my index finger. His mouth and his anus are one. I am at the center of feeling. Anne Sexton
Also, the index finger and the little finger have an extra extensor, used for instance for pointing. Source: Internet
Ecoffey testified under oath, "He (Peltier) held his hand like this," she said, pointing her index finger like a gun, "and he said 'that (expletive) was begging for his life but I shot him anyway.' Source: Internet