Researchers have remarked and recoiled at the literature confusion regarding the meanings of trust and distrust. The problem involves both the proliferation of narrow intra-disciplinary research definitions of trust and the multiple meanings the word trust possesses in everyday use. To enable trust researchers to more easily compare empirical results, we define a cohesive set of conceptual and measurable constructs that captures the essence of trust and distrust definitions across several disciplines. This chapter defines disposition to trust (and-distrust) constructs from psychology and economics, institution-based trust (and-distrust) constructs from sociology, and trusting/distrusting beliefs, trusting/distrusting intentions, and trust/distrust-related behavior constructs from social psychology and other disciplines. Distrust concepts are defined as separate and opposite from trust concepts. We conclude by discussing the importance of viewing trust and distrust as separate, simultaneously operating concepts.