Culture medium is a type of material used to grow and maintain microorganisms in laboratory settings. The two crossword solutions for the term culture medium are AGAR (4 letters) and AGARS (5 letters). AGAR is a gelatinous substance derived from seaweed, and agars are the plural form of AGAR. AGAR is commonly used as a culture medium in microbiology, as it provides a solid surface for the growth of microorganisms.