agar
n. uncountablen. a jelly-like substance made from seaweed. Scientists use it in labs to grow bacteria, and cooks use it to thicken food.
n. a gelatinous substance obtained from various kinds of red algae. Used primarily as a solidifying agent in culture media for microbiological research and as a vegan alternative to gelatin in food preparation.
The scientist put the bacteria on a plate of agar.
The lab technician prepared several petri dishes with nutrient-rich agar to test the water samples for contamination.
Because it remains solid at higher temperatures than gelatin, agar is the preferred medium for incubating human pathogens that require a stable environment at body temperature.
Typically uncountable when referring to the substance; can be countable when referring to specific types or prepared plates.