numeric, prefix

壱, 弌 and 壹 are used in legal documents.
  1. one, 1.

takes genitive case の, suffix

  1. best.

takes genitive case の

  1. first, foremost.

noun

  1. beginning, start.

noun used as a prefix

Before a noun.
  1. a (single), one (of many).

noun

  1. Messages.cards.ace.
  2. bottom string (on a shamisen, etc.).

Variations

Pronunciation Kanji Kana Is Common
いち
いち
いち
いち
いち

Contained Kanji Breakdown

one, one radical (no.1)
イチ いっ ひと- (1st, N5)