Three or third
In an American context, Tra is most often used as a phonetic nickname for a boy who is the third in his family to carry the same name (a 'III'). It is also found in Vietnamese culture, where it can refer to a type of flower or tea.
Less common today
Tra isn't in the latest US Top 1000. It last peaked at #2,252 in 1992.
American actor known for the series Empire
Former NFL safety
Former NFL offensive tackle
US births per 5-year period, 1990βpresent (SSA data).