Cos

UK: /ˈkɒs/ US: /kɑs, kɔs/ ,(kos, kôs)

Collins Concise English Dictionary © HarperCollins Publishers::

Cos / kɒs/ noun

1. a variant spelling of Kos

WordReference Random House Learner's Dictionary of American English © 2026

cos /kɑs, kɔs/   n. 

1. Food romaine.

cos,  an abbreviation of:

1. Mathematics cosine.

cos.,  an abbreviation of:

1. companies.
2. counties.

WordReference Random House Unabridged Dictionary of American English © 2026

cos¹  (kos, kôs), n. 

1. Plant Biology romaine.

• after Kos, where it originated 1690–1700

cos² ,

1. Mathematics [Trigonom., Math.] cosine.

Cos  (kos, kôs), n. 

1. Place Names Kos.

cos., 

1. companies.
2. Government consul.
3. Government consulship.
4. counties.

C.O.S., 

1. Business cash on shipment.

Also, c.o.s. 

Collins Concise English Dictionary © HarperCollins Publishers::

cos, cos lettuce / kɒs/ noun

1. a variety of lettuce with a long slender head and crisp leaves
   Usual US and Canadian name: romaine

Etymology: 17th Century: named after Kos, the Aegean island of its origin

cos / kɒz/ abbreviation

1. cosine

Collins Concise English Dictionary © HarperCollins Publishers::

Kos, Cos / kɒs/ noun

1. an island in the SE Aegean Sea, in the Greek Dodecanese Islands: separated from SW Turkey by the Kos Channel; settled in ancient times by Dorians and became famous for literature and medicine. Pop: 30 947 (2001). Area: 282 sq km (109 sq miles)