SMB: server message block; a Microsoft file and printer sharing protocol.
CIFS: common Internet filesystem; around 1996, Microsoft decided that SMB needed the word Internet in it, so they changed it to CIFS.
Direct-Hosted: a method of providing file/printer sharing services over port 445/TCP only, using DNS for name resolution instead of WINS.
NetBIOS: network basic input/output system. This is not a protocol; it is a method of communication across an existing protocol. This is a standard originally developed for IBM by Sytek in 1983. To exaggerate the analogy a bit, it can help to think of this in comparison to your computer's BIOS--it controls the essential functions of your input/output hardware-- whereas NetBIOS controls the essential functions of your input/output traffic using the network.
NBT: NetBIOS over TCP; also known as NetBT. This is an important concept. NBT allows NetBIOS traffic to be proxied over TCP/IP. As a result, NetBIOS names are made equivalent to IP addresses, and NetBIOS name types conceptually are equivalent to TCP/IP ports. This is how file and printer sharing are accomplished in Windows 95/98/ME. They traditionally rely on three ports: NetBIOS Name Service (nbname) via UDP port 137, NetBIOS Datagram Service (nbdatagram) via UDP port 138 and NetBIOS Session Service (nbsession) via TCP port 139. All name resolution is done with WINS, NetBIOS broadcasts and DNS. NetBIOS over TCP is documented in RFC 1001 (concepts and methods) and RFC 1002 (detailed specifications).