The experiments conducted in this research aimed to increase our understanding of olfactory properties and classify them hierarchically through entailment. The research objective was to build an odor classification based on internal knowledge (i.e. mental context). Twelve floral scents were described freely by 60 participants. First, three sensory judges undertook a semantic analysis of the 1145 olfactory terms gathered. Secondly, a study of the entailment between olfactory properties was conducted using 42 subjects working on four lists of terms describing the characteristics of floral perfumes. The results confirmed the hypothesis that olfactory properties show tree-like structure. This allowed us to propose a classification system composed of two superordinate categories: First, objects, being olfactory sources, constitute the first category and are considered as olfactory properties themselves (i.e. civilization, food and natural sources). Second non-objects properties are those applic- able to a diversity of objects: (i.e. properties, such as objects’ physical state: sensory, intensity, space, time) and those related to the subject (as personal feelings and value judgments). Based on these results, it appears that olfactory properties can be organized as a semantic network in line with the general theory of categorization.