Segment Routing divides a network path into several segments which may include Nodes and links.
And assigns a segment ID (SID) to each segment and forwarding node.
A prefix segment identifier (SID) usually identifies a segment routing tunnel destination which is the loopback ip address of the destination node.
An Adjacency Segment Identifier (adj-SID) is a local label, automatically created by IGP and it that points to a specific interface.
