A fetus (pronounced /ˈfiːtəs/; also spelled foetus, fœtus, faetus, or fætus, see below) is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.

In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.

The word fetus (plural fetuses) is from the Latin fētus (“offspring”, “bringing forth”, “hatching of young”). It has Indo-European roots related to sucking or suckling, from the Aryan prefix bheu-, meaning "To come into being".

Fœtus or foetus is the British, Irish and Commonwealth spelling, which has been in use since at least 1594. It arose as a hypercorrection based on an incorrect etymology (i.e. due to insufficient knowledge of Latin) that may have originated with an error by Saint Isidore of Seville, in AD 620. This spelling is the most common in most Commonwealth nations (except in medical literature, where its use is barred). The etymologically correct original spelling, fetus is used in Canada and the United States. In addition, fetus is now the standard English spelling throughout the world in medical journals. The spelling "faetus" was used historically.

Francesco (Franco) Battiato (born 23 March 1945 in Riposto) is an Italian singer-songwriter, composer, filmmaker and, under the pseudonym Süphan Barzani, also a painter. Battiato's songs contain esoteric, philosophical and religious themes. His collaborations from 1994 onward with the nihilistic-cynical philosopher Manlio Sgalambro have added lyrical references to Emil Cioran, Friedrich Nietzsche and other anarchistic thinkers.

Together with Alice, Franco Battiato represented Italy at the Eurovision Song Contest 1984 with the song "I treni di Tozeur".

Franco Battiato was born in 1945 in Riposto (in the former municipality of Jonia, that included also Giarre) in the province of Catania, Sicily.

At the age of 20 he moved to Milan and in 1967 he obtained the first musical contract. His single La Torre was released and Battiato appeared on TV to perform the song. He scored some success with the romantic song È l'amore. After further covers of pop songs, he met the experimental musician Juri Camisasca in 1970 and collaborated with Osage Tribe, an Italian psychedelic-progressive rock band. As a solo artist, he released the science-fiction single La convenzione (The convention), one of the finest Italian progressive rock songs of the 1970s.