Synonyms for Cos lettuce:

n.

cos lettuce (noun)
cos, romaine, romaine lettuce, Lactuca Sativa Longifolia.
vegetables (noun)
aubergine, Bok Choy, beet, artichoke, bell pepper, arugula, bamboo shoots, asparagus, acorn squash, beetroot.

Other synonyms:

Lactuca sativa longifolia
Lactuca Sativa Longifolia.