Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
dotted line [ˈdɔtɪd-] n пункти́рная ли́ния
to sign on the dotted line (fig) оконча́тельно соглаша́ться (согласи́ться perf)
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.
Русский: