The Opposite of Infinity - Numberphile (youtube.com)
Continuing to talk Infinitesimals, this time with Dr James Grime.- Infinitesimal (Wikipedia)
In mathematics, an infinitesimal number is a non-zero quantity that is closer to 0 than any non-zero real number is. The word infinitesimal comes from a 17th-century Modern Latin coinage infinitesimus, which originally referred to the “infinity-eth” item in a sequence.