Complex sentence: Because of this difficulty, some people (though generally not botanists) use a second set of terms to describe different types of gynoecia, the basic unit of which is the pistil (from Latin "pistillum" "pestle").
Split into simpler sentences: Because of this difficulty, some people (though generally not botanists) use another term to describe the visible structure (s) in a gynoecium. This term is pistil (from Latin "pistillum" "pestle").