cos

¹ American

[kos, kaws] / kɒs, kɔs /

noun

romaine.

cos ² American

abbreviation

Trigonometry, Mathematics. cosine.

cos. ³ American

abbreviation

companies.
consul.
consulship.
counties.

C.O.S. ⁴ American

Or c.o.s.

abbreviation

cash on shipment.

COS ¹ British

abbreviation

Chief of Staff

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Cos ² British

/ kɒs /

noun

a variant spelling of Kos

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

cos ³ British

/ kɒz /

abbreviation

cosine

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

cos ⁴ British

/ kɒs /

noun

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

cos Scientific

Abbreviation of cosine

Etymology

Origin of cos

1690–1700; after Kos, where it originated

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

"I just started stuffing cheese in my mouth cos I can't stop grinning. Isn't it funny? I was so nervous when Claudia squeezed my shoulder blade, and now I just love being a traitor."

From BBC • Oct. 22, 2025

In brief, the TerS subunit initiates packaging when it encounters a specific site called cos in the genome.

From Science Daily • Nov. 21, 2023

"I saw him again years later, cos we hadn't particularly left on good terms after Hammersmith, and it was good," he said.

From BBC • Jul. 4, 2023

Figure 27.42 A polarizing filter transmits only the component of the wave parallel to its axis, E cos θ , reducing the intensity of any light not polarized parallel to its axis.

From Textbooks • Aug. 12, 2015

“Dad was dead chuffed . . . thought I migh’ not be a wizard, see, cos me mum . . . well, anyway.

From "Harry Potter And The Goblet Of Fire" by J. K. Rowling

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023