This study aimed to analyze the ecolexicon and morphology by typology in the community of Mandailing (BM) agriculture. Qualitative methods were used. Data were collected using several stages such as interviews, self-examination, documenting and note-taking. The study was carried out in areas where income was dominated by farming, precisely in South Tapanuli Regency. The results showed that the biotic environment in the lexicon was 36 or around 70.5%, and the abiotic environment was 15 or around 29.5%. The typology of words was dominated by nominal (39), verbs (7), and adjectives (2). Based on the exposure to ecolexicon forms and typologies found in the Mandailing language, several conclusions can be drawn: the lexicon found in BM has affixations such as prefixes (si-); there are other prefixes (ma-, mam-, mar-, mang-); and the suffix form (-on) is often used to express farming activities, when associated with nouns, which is an activity that is carried out to indicate the type of rice and banana. The main reason for the loss of the lexicon is that many traditional activities have been replaced by modern means.
Keywords: Ecolinguistic, Mandailing, Community Agriculture