Electrical connectors are classified by conductor configuration, size, and attachment method. Compression Connectors are connectors which are "attached" to conductors with the use of compression tools and dies.
Other attachment options are solder,mechanical capture, and pin-connection.
Compression Connectors and compression attachment are chosen when conductivity and secureness of conductor performance requirements are high. That is, compression connection, by virtue of compressing the conductor and cable within constrained crimp die geometry produces a connection which approaches most closely the conductivity and tensile strength of the conductor.