3H

English

Noun

3H (usually uncountable, plural 3Hs)

1. (British English) A grade of pencil with lead that makes lighter marks than a pencil grade 2H but darker marks than a pencil of grade 4H; a pencil with hard lead.
2. A pencil of grade 3H.
3. tritium. In this case, it is preferable that the "3" should be superscripted: ³H.