1. Noun

   iron (Fe)

   鉄は最も有用な金属です。

2. steel

   see 鋼

3. Noun which may take the genitive case particle 'no', Noun

   iron (will, discipline, lady, etc.)

4. Noun, Noun, used as a suffix, Noun, used as a prefix

   railway

   Abbreviationsee 鉄道

5. Noun, used as a suffix

   railway enthusiast

   Colloquial

Also written 鐵【てつ】tetsu