In this paper we focus on the notion of majority in multi-agent (group) decision making. In group decision making the reduction of the decision makers opinions into an overall, representative opinion is usually performed through an aggregation process. In this paper we focus on the problem of defining an opinion synthesizing the majority of the experts; to this aim we propose a formalization of the concept of majority opinion as a fuzzy subset (fuzzy majority opinion). As we shall see this approach provides in addition to a value for a majority opinion also an indication of the strength of that value being used as the majority opinion. This fuzzy subset can be interpreted as a possibility distribution over the possible representatives of a majority opinion over a set of values.