もし

Etymology
From ; attested in the  of 759. In turn, reconstructed as deriving from.

Adverb

 * 1)   if; supposing
 * 2)   perhaps
 * 1)   perhaps

Affix

 * 1)   or maybe

Usage notes

 * The word is used at the start of the clause serves as a signal that it's conditional and can be omitted. Other grammatical forms and words are still used to indicate the condition.