Fitra is an Arabic word meaning 'innate human nature'. However, other common translations include "primordial nature" and "innate disposition".
According to Islamic theology, human beings are born with an innate knowledge of tawhid, which is encapsulated in the fitra along with intelligence, ihsan and all other attributes that embody what it is to be human. It is for this reason that some muslims prefer to refer to those who embrace Islam as reverts rather than converts, as it is believed they are returning to a pure state.
The perfect embodiment of fitra was Abraham and Muhammad.
Narrated Abu-Huraira:
Allah's Apostle said, "No child is born except on Al-fitra (Islam) and then his parents make him Jewish, Christian or Magian (Zoroastrian), as an animal produces a perfect young animal: do you see any part of its body amputated?"
- Sahih al-Bukhari, Volume 2, Book 23, Number 441
Islam holds that Adam possessed fitra (innate nature) that allowed him knowledge of Allah. Subsequent generations are born with such an innate knowledge of Allah and His tawhid, but this knowledge has to be manifested through religious education as sin leads to heedlessness and ignorance of Allah. Therefore, prophecy acts as a reminder (dhikr), according to the mercifulness of Allah and allows the actualisation of fitra.