tra-, tract-, trac-, -tractive, -traction, -tracting, treat-, trai-

(Latin: drag, draw together; a drawing out or pulling)

retreat, retreats, retreated, retreating (verb forms)
retreating back
sphere of attraction
1. The distance within which the potential energy arising from mutual attraction of two molecules is not negligible with respect to the molecules' average thermal energy at room temperature.
2. In physical chemistry, the area between two molecules within which the energy generated by their mutual attraction is significant enough to be distinguished from the average energy of other molecules in the system.
subcontract (s) (noun), subcontracts (pl)
A document assigning to another party some of the obligations of a previous agreement: "A secondary contract in which the person or company originally hired in turn hires someone else to do all or part of the work."
subcontractor (s) (noun), subcontractors (pl)
A person who works on a project with a person or company who also agrees to work on some of the project obligations of the primary company.
subtract, subtracts, subtracted, subtracting (verb forms)
tetractine, tetraxon (s) (noun); tetractines; tetraxons (pl)
A spicule of four equal and similar rays; tetract: The four tetractines of a sponge meet at equal angles.