Meaning of 3H | Babel Free

Definitions

1. 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.
   British, English, uncountable, usually
2. A pencil of grade 3H.
   uncountable, usually
3. tritium. In this case, the "3" should be superscripted: ³H.
   uncountable, usually

CEFR level