Meaning negotiation (MN) is the general process with which agents reach an agreement about the meaning of a set of terms. We give here a general model of MN for two agents, in which each agent discusses with the other one her viewpoint by exhibiting it in an actual set of constraints on the meaning of the negotiated terms. We call this presentation of individual viewpoints an angle. The two agents do not aim at forming a common viewpoint but, instead, at agreeing about an acceptable common angle. We formalize the process of reaching such an agreement by giving a deduction system that comprises of rules that are consistent and adequate for representing MN.