Boulevard and Throughway

Boulevard noun - A passage cleared for public vehicular travel.

Throughway and boulevard are semantically related In some cases you can use "Throughway" instead a noun "Boulevard".

Throughway noun - A broad highway designed for high-speed traffic.

Boulevard and throughway are semantically related in road topic. You can use "Boulevard" instead a noun "Throughway", if it concerns topics such as path upon which travel occurs.