This study was conducted using an ethnographic approach with the aim of documenting, describing, and analyzing the indigenous knowledge system related to the Elaeagnus angustifolia (Russian olive or “senjed”) tree in Semnan Province, Iran. Data were collected through participant observation and in-depth ethnographic interviews with 27 local orchardists and knowledge holders from various areas of the province, using purposive sampling, and were analyzed through thematic analysis. The findings of this ethnographic research, in addition to documenting local names and native varieties, reveal the multifaceted roles of senjed in everyday life in the past, including its culinary, hygienic–cleaning, fuel, and potential medicinal uses within its cultural context. Furthermore, the reflection of senjed in oral literature, including proverbs, songs, and local descriptions, was analyzed as part of the community’s cultural material. The study emphasizes that senjed, beyond being an orchard product, constitutes an element of the region’s intangible cultural heritage and historical subsistence economy, and that ethnographic methodology provides an essential tool for a deep, contextualized, and systematic understanding of these cultural connections ethnographic approach with the aim of documenting, describing, and analyzing the indigenous knowledge system related to the Elaeagnus angustifolia (Russian olive or “senjed”) tree in Semnan Province, Iran. Data were collected through participant observation and in-depth ethnographic interviews with 27 local orchardists and knowledge holders from various areas of the province, using purposive sampling, and were analyzed through thematic analysis. The findings of this ethnographic research, in addition to documenting local names and native varieties, reveal the multifaceted roles of senjed in everyday life in the past, including its culinary, hygienic–cleaning, fuel, and potential medicinal uses within its cultural context. Furthermore, the reflection of senjed in oral literature, including proverbs, songs, and local descriptions, was analyzed as part of the community’s cultural material. The study emphasizes for a