「五」(go) means "five" or "5". It's a basic number used for counting various items, people, or in general numerical expressions. For example, to say "five things," you would use 「五つ」(itsutsu). This is a core number in Japanese counting.

「五」(ご)は「5」を意味(いみ)します。物(もの)を数(かぞ)える時(とき)や数量(すうりょう)を示(しめ)す時(とき)に使(つか)います。例(れい)：「五」(いつ)つ。