apeiron is incorrectly written, and should be written as "apeiron" being its meaning: apeiron = Apeironlos Greek philosophers were the first to ask what is formed the universe. Such of Mileto ( 639-546 B.c. ) He believed that everything came from the water. Later, Leucippus of Miletus ( s. V. B.c. ) and his pupil Democritus of Abdera ( 460 BC -? ) they formulated the concept of atom, what remains when the matter no ( ±-) You can cut (TO DO ¼ ¿½ ) or more divided. But before such and Leucippus, Anaximander ( 610 -? BC ) He was referring to a single substance, without form, without limit and that is the principle of all things. This substance called it ±aµ¹a ½ ( 41 apeiron; formed from the prefix of negation ±-( a - = No )? and the word aµ¹a±a ( peirar = limit, end, extremity, frontier ) that is, without borders, or infinite. Not obnstante " to apeiron " in philosophy, starting from Anaximander, also means that it can not be you logical limits, i.e., that which cannot be defined. Referred this to a nameless universal substance without form, which was not nor water, Earth, air, nor fire, but gave origin to all of them. Thus, in philosophy " to apeiron " It means the indefinite, which cannot be defined not to be anything specific.