Is tcpdump a client of rpcpad and implemented in pcap?

https://www.tcpdump.org/index.html#documentation has manpages for pcap, tcpdump, and rpcapd, but I don't find what relation is between the three. Is pcap a C library for implementing a client of rpcapd? Is tcpdump a client of rpcpad and therefore dependent on rpcpad? Is tcpdump implemented in pcap?