syndactyly

From syn- +‎ Ancient Greek δάκτυλος (dáktulos, “finger”) +‎ -y.

syndactyly (countable and uncountable, plural syndactylies)

1. (biology) The normal condition, in some animals and birds, of having fused digits.
2. (teratology) The anomalous condition, in humans, of having some fingers or toes fused with a web.
   • 2008, Guinness World Records — Human Body — Extreme Bodies — Most Fingers and Toes — Living Person

     Pranamya Menaria (India; born August 10, 2005) has 25 in total (12 fingers and 13 toes). This is as a result of the condition Polydactyly and Syndactyly.

• syndactylism

• polysyndactyly