| Noun | 1. | butterhead lettuce - lettuce with relatively soft leaves in a loose head; easily broken or bruised lettuce - leaves of any of various plants of Lactuca sativa buttercrunch - lettuce with delicate and relatively crunchy leaves Bibb lettuce - lettuce with relatively crisp leaves Boston lettuce - lettuce with relatively soft leaves head lettuce, Lactuca sativa capitata - distinguished by leaves arranged in a dense rosette that develop into a compact ball |