Sense file
How the sense moved
The archive follows the dated record first, then reads the social or rhetorical pressure that hardened, softened, narrowed, or reversed the word.
Older meaning
A ball of thread.
Modern meaning
A hint or piece of evidence.
Research lens
A clean metaphor story: a physical guide became an intellectual guide.
Meaning trail
Root
thread
The original object was textile, not detective fiction.
Bridge
guiding thread
A path-finding metaphor helped the semantic turn.
Now
hint or evidence
The thread became an intellectual handle.