NOD

[noun] [C usually singular]Each gave the other a quiet nod of recognition across the crowded room.(informal) 'A nod's as good as a wink (to a blind horse/man)' means that only a slight sign is needed to make something clear because a situation is already understood well.(UK informal) If a suggestion is approved on the nod it is accepted without discussion.The new proposal went through on the nod.A nodding acquaintance is a person whom you know slightly, or a slight knowledge of a subject.I know him as a nodding acquaintance but nothing more.She has only a nodding acquaintance with the issues involved.