Algebra - Abstract algebra. 1  Abstract algebra extends the familiar concepts found in elementary algebra and arithmetic of numbers to more general concepts.
Choose the freshest looking lettuce for storing. Photo Credit anna1311/iStock/Getty Images. Romaine lettuce's high water content means there is no long-term preservation method suitable for making the lettuce last longer. Drying, canning and freezing all produce inedible results. For the best nutritional value, romaine lettuce is best served when it's fresh, green and crisp. Storing the lettuce in a refrigerator is the best option for preserving it, although there are a few other measures that can be taken to ensure romaine lettuce lasts as long as possible.
Noun. 1. head lettuce-distinguished by leaves arranged in a dense rosette that develop into a compact ball. Lactuca sativa capitata. butterhead lettuce-lettuce with relatively soft leaves in a loose head; easily broken or bruised.crisphead lettuce, iceberg lettuce, iceberg-lettuce with crisp tightly packed light-green leaves in a firm head; iceberg is still the most popular lettuce.genus Lactuca, Lactuca-an herb with milky juice: lettuce; prickly lettuce. lettuce-any of various plants of the genus Lactuca.oun. 1. head lettuce-distinguished by leaves arranged in a dense rosette that develop into a compact ball. Lactuca sativa capitata. butterhead lettuce-lettuce with relatively soft leaves in a loose head; easily broken or bruised.