Earth or land
Tierrah is a modern creative spelling of Tierra, which is the Spanish word for earth or land. It is often chosen by parents looking for a nature-inspired name with a unique, phonetic flair. The addition of the 'h' at the end distinguishes it from the common noun while maintaining its grounded meaning.
Less common today
Tierrah isn't in the latest US Top 1000. It last peaked at #6,930 in 1991.
US births per 5-year period, 1990βpresent (SSA data).