The term 'PERTAINING TO PLANTS' can be summarized by two crossword solutions: Botanic (7 letters) and BOTANICAL (9 letters). Botanic is derived from the Greek word 'botanikos' which means 'of plants' or 'pertaining to plants'. BOTANICAL is an adjective that refers to plants, their structure, and their properties. Both words are used to describe anything related to plants, such as botany, the scientific study of plants.