What is a network standard or a protocol that defines how data or massages are routed form one end of network to the other?

it all depends on what topology the network is using.

ARCNET

AppleTalk

ATM

Bluetooth

DECnet

Ethernet

FDDI

Frame relay

HIPPI

IEEE 1394 aka FireWire, iLink

IEEE 802.11 aka Wireless LAN (Wi-Fi certification)

IEEE-488

internet protocol suite

IPX

Myrinet

OSI protocol suite

QsNet

RS-232

SPX

System Network Architecture

Token ring

USB

X.25 protocol suite