trail; clues; thread (of a story)

(electricity) line; circuit; wire; (traffic) road; track; route

line (in drawing, calligraphy etc); the lines or contours of a three-dimensional object (hairstyle, clothing, car etc)

tip-off

spy; informer

itinerary; route; political line (e.g. right revisionist road); CL:條|条[tiao2]

front line; military front; workface; cutting edge

line of sight

light ray; CL:條|条[tiao2],道[dao4]; light; illumination; lighting (for a photograph)

wire; power cord; CL:根[gen1]