expert witness

noun1

1. •
   A witness that has expertise in a certain field.

   • October 23 2012, Nicolas Bourcier in Guardian Weekly, Brazil comes to terms with its slave trading past In a sensational decision this April the 10 supreme court judges unanimously ruled in favour of positive discrimination in higher education, declaring that the racial quotas in Brazilian universities were constitutional and redressed the "social debt of slavery". Dozens of expert witnesses were heard and the ruling was televised live.