What does "runner" mean?

Additional senses

1. 2.A messenger. Swift.
2. 3.A smuggler. [Colloq.] R. North.
3. 4.One employed to solicit patronage, as for a steamboat, hotel, shop, etc. [Cant, U.S.]
4. 5.(Bot.) A slender trailing branch which takes root at the joints or end and there forms new plants, as in the strawberry and the common cinquefoil.
5. 6.The rotating stone of a set of millstones.
6. 7.(Naut.) A rope through a block and used to increase the mechanical power of a tackle. Totten.
7. 8.One of the pieces on which a sled or sleigh slides; also the part or blade of a skate which slides on the ice.
8. 9.(Founding) (a) A horizontal channel in a mold, through which the metal flows to the cavity formed by the pattern; also, the waste metal left in such a channel. (b) A trough or channel for leading molten metal from a furnace to a ladle, mold, or pig bed.
9. 10.The movable piece to which the ribs of an umbrella are attached.
10. 11.(Zoöl.) A food fish (Elagatis pinnulatis) of Florida and the West Indies; -- called also skipjack, shoemaker, and yellowtail. The name alludes to its rapid successive leaps from the water.
11. 12.(Zoöl.) Any cursorial bird.
12. 13.(Mech.) (a) A movable slab or rubber used in grinding or polishing a surface of stone. (b) A tool on which lenses are fastened in a group, for polishing or grinding.