Cos Lettuce: What's Another Name for Romaine Lettuce?

December 21, 2025 •

3 min read

The origins of romaine lettuce are ancient, with historical evidence suggesting cultivation as far back as 5,000 years ago in Egypt. This long history has given rise to one of its most recognizable aliases, leading many to wonder, "what's another name for romaine lettuce?" The answer lies in both geography and history, as this versatile vegetable is also widely known as cos lettuce.

Quick Summary

Romaine lettuce is also known as cos lettuce, with the name difference being largely a matter of regional preference and historical lineage. While Americans predominantly use 'romaine', British and other English-speaking countries more commonly refer to it as 'cos', after the Greek island of Kos.

Key Points

Cos Lettuce: The primary alternative name for romaine lettuce, especially common in the UK, stemming from the Greek island of Kos.
Regional Naming: The name "romaine" is prevalent in North America, while "cos" is used more widely in British English, reflecting the lettuce's historical path through Rome.
Culinary Staple: This sturdy, crisp lettuce is the classic choice for Caesar salads due to its ability to hold up against creamy dressings.
High in Nutrients: Compared to watery iceberg lettuce, romaine (cos) is a much more nutrient-dense option, particularly high in vitamins A and K.
Versatile Use: Beyond raw salads, its robust leaves are tolerant of heat, making it suitable for grilling, braising, and wraps.
Distinct Texture: The long, upright leaves and firm central rib give romaine/cos a distinct, crunchy texture that differs from softer butterhead or loose-leaf varieties.

Cos and Romaine: One and the Same

The most common alternative name for romaine lettuce is cos lettuce. This regional difference in terminology is one of the most persistent naming quirks in the culinary world. In North America, the term "romaine" is standard, but travel across the Atlantic to the United Kingdom, and you'll find it predominantly labeled as "cos". Despite the different names, there is no substantive difference between the two; they are the same variety of Lactuca sativa.

The Etymology Behind the Names

The story of the two names is a tale of trade routes and imperial history. The name "cos" is believed to be derived from the Greek island of Kos, or Cos, where the lettuce is thought to have originated. This explains its widespread use in British English and other regions that have been historically influenced by Mediterranean trade. The name "romaine," on the other hand, arrived in Western Europe via Rome. In Italian, it is called lattuga romana and in French, laitue romaine, both translating to "Roman lettuce." As a result, the name "romaine" is the common term used in North America.

A Comparison of Lettuce Varieties

To better understand romaine/cos lettuce, it helps to compare it to other common types. Its firm texture and upright growth set it apart from its leafy cousins.


Feature	Romaine / Cos	Iceberg Lettuce	Butterhead (Bibb/Boston)	Leaf Lettuce
Head Shape	Elongated, upright	Tight, round head	Loose, soft head	No head, loose leaves
Leaf Texture	Sturdy, crisp	Very crunchy	Soft, buttery	Tender, delicate
Flavor Profile	Slightly bitter, robust	Mild, very watery	Sweet, delicate	Mild to slightly earthy
Best For	Caesar salads, wraps	Added crunch for sandwiches	Wraps, delicate salads	Mixed green salads
Nutritional Value	High in vitamins A & K	Lower in nutrients	Good source of vitamins A & K	High in vitamins A & C

Culinary Versatility and Nutritional Benefits

Romaine or cos lettuce is a staple in many kitchens because of its adaptability. The sturdy leaves are perfect for standing up to rich dressings, which is why it is the classic choice for a Caesar salad. Its crunchy texture and slightly peppery flavor add depth to sandwiches and burgers. Beyond salads, the heat tolerance of this lettuce means it can also be lightly grilled or added to stir-fries, which can mellow its flavor and add a different culinary dimension. Nutritionally, romaine outpaces iceberg significantly, containing high levels of vitamin A and vitamin K. It's a nutrient-dense choice for any meal.

Sub-varieties and Modern Context

Beyond the primary names, the market features some common sub-varieties and cuts. For instance, Little Gem is a compact, smaller version of cos lettuce with a sweeter flavor, making it popular for garnish and appetizers. You may also see "romaine hearts" sold in stores, which are the inner, more tender leaves of the head, with the tougher outer leaves removed. In recent years, romaine has also gained prominence in discussions around food safety, particularly regarding E. coli outbreaks, making proper washing and handling crucial for consumers.

Conclusion

Whether you call it romaine or cos, this durable and flavorful lettuce is the same plant with a rich history and a versatile place in the kitchen. The different names are simply a reflection of its journey from the Aegean to the rest of the world. So, the next time you hear someone mention cos lettuce, you'll know that it is simply another name for the familiar and crisp romaine. Its robust texture and nutritional profile ensure it remains a popular choice for salads and a variety of other culinary applications worldwide. For more on the specific characteristics and safe handling of this leafy green, consider this source: Romaine Lettuce - Wikipedia.

Frequently Asked Questions

Yes, cos lettuce and romaine lettuce are the same variety of lettuce. The different names are simply a matter of regional terminology, with 'cos' being more common in the UK and 'romaine' used in North America.

The name 'cos' is believed to originate from the Greek island of Kos, or Cos, where the lettuce was supposedly first cultivated and introduced to other parts of Europe.

The name 'romaine' comes from its historical association with the city of Rome, where it was called lattuga romana (Roman lettuce). It reached Western Europe via Rome, and this name became common in North America.

There is no nutritional difference, as they are the same plant. Romaine/cos is generally more nutritious than iceberg lettuce, containing higher levels of vitamins A and K.

Romaine hearts are the inner, more tender leaves of the romaine/cos head, sold after the tougher, outer leaves have been trimmed away. They are valued for their sweetness and crispness.

Yes, unlike some other lettuces, romaine is tolerant of heat and can be cooked. It holds up well to grilling, braising, or adding to stir-fries.

Little Gem is a sub-variety of cos lettuce. It is a compact, smaller version with tightly packed leaves and a slightly sweeter flavor than the standard size.