protocol

noun

pro·​to·​col ˈprō-tə-ˌkȯl 

-ˌkōl,

-ˌkäl,

-kəl

1

a

: a system of rules that explain the correct conduct and procedures to be followed in formal situations

They did not follow the proper diplomatic protocols.

The student then walked up on stage to have her books signed by Thomas and Johnson—a breach of protocol that became a scene of sweet solidarity.

—Jireh Deng

b

: a set of conventions governing the treatment and especially the formatting of data in an electronic communications system

network protocols

The move to Cloudfare makes app blocking much more complicated, as the new system uses dynamic internet protocols (IPs) that change constantly.

—Rebecca Falconer

c

: usage or custom especially in social matters : convention sense 3a,b

What is the proper protocol for declining a job offer?

In an organization that prides itself on its manners, the incident was seen by some as a violation of protocol.

—Clifford J. Levy

2

: a detailed plan of a scientific or medical experiment, treatment, or procedure

an experimental protocol

concussion protocol in the NFL

After a six-week break, which was the second phase of the study, the protocol shifted for phase three: each of the two groups received the opposite treatment for another six weeks.

—Anton Benz

3

: an original draft, minute, or record of a document or transaction

4

a

formal : a preliminary memorandum often formulated and signed by diplomatic negotiators as a basis for a final convention or treaty

… called on the government to amend or remove a protocol to the treaty …

—Joe Joyce

b

formal : the records or minutes of a diplomatic conference or congress that show officially the agreements arrived at by the negotiators

Did you know?

Protocol and Politics

In Late Greek, the word prōtokollon referred to the first sheet of a papyrus roll bearing the date of its manufacture. In some instances, it consisted of a flyleaf that was glued to the outside of a manuscript's case and provided a description of its contents. Coming from the Greek prefix prōt- ("first") and the verb kollan ("to glue together"), prōtokollon gave us our word protocol. In its earliest uses in the 15th century, the word referred to a record of a document or transaction. By the turn of the 18th century it was being used for the original record or minutes of a diplomatic negotiation, and still later for the etiquette observed by heads of state in ceremonies and relations with other dignitaries. This sense has since extended in meaning to cover any code of proper conduct.

Examples of protocol in a Sentence

Typically, those who make pronouncements like this assume (without saying so) that the tongues making up the multitude will belong to persons who are committed to the protocols of rational inquiry; frivolous persons, persons who exploit those protocols or play with them to gain political ends, are not imagined. —Stanley Fish, Harper's, December 2005

Purcell even flouted the timeless protocol of pretending to admire the work of his fellow editors. —Tobias Wolff, Old School, 2003

Today, thanks to the civil-rights movement, white guilt is propriety—an utterly invisible code that defines decency in our culture with thousands of little protocols we no longer even think about. —Shelby Steele, Harper's, November 2002

The soldier's actions constitute a breach of military protocol.

They did not follow the proper diplomatic protocols.

What is the proper protocol for declining a job offer?

the Geneva Protocol of 1925

Recent Examples on the Web

There's [a] protocol that is different. —Janine Rubenstein, PEOPLE, 1 Nov. 2025

Robinson will be required to pass the NFL’s four-stage concussion protocol to return to practice, and to games. —Omar Kelly updated October 31, Miami Herald, 31 Oct. 2025

The department is responsible for ensuring safety protocols are followed through every stage of spacecraft development and testing, and when scientists and engineers interface with potential hazards like high-pressure procedures, vacuum chambers, radioactive materials and heavyweight hardware. —Josh Dinner, Space.com, 31 Oct. 2025

The last time this protocol was invoked was in 1936 with the abdication of Edward VIII. —Christian Edwards, CNN Money, 31 Oct. 2025

Word History

Etymology

Middle French prothocole, from Medieval Latin protocollum, from Late Greek prōtokollon first sheet of a papyrus roll bearing date of manufacture, from Greek prōt- prot- + kollan to glue together, from kolla glue; perhaps akin to Middle Dutch helen to glue

First Known Use

15th century, in the meaning defined at sense 3

Phrases Containing protocol

• hypertext transfer protocol

Rhymes for protocol

• aerosol
• alcohol
• arbitral
• basketball
• butanol
• cannonball
• carbinol
• catarrhal
• cortisol
• ethanol
• fireball
• gasohol

Podcast

Get Word of the Day delivered to your inbox!

Kids Definition

protocol

noun

pro·​to·​col ˈprōt-ə-ˌkȯl 

1

: an original copy or record of a document

2

: a code of diplomatic or military rules of behavior

3

: a set of rules for the formatting of data in an electronic communications system

network protocols

Medical Definition

protocol

noun

pro·​to·​col ˈprōt-ə-ˌkȯl, -ˌkōl, -ˌkäl 

1

: an official account of a proceeding

especially : the notes or records relating to a case, an experiment, or an autopsy

2

: a detailed plan of a scientific or medical experiment, treatment, or procedure

cryotherapy was performed in approximately half of the eyes through a randomization protocol

—The Journal of the American Medical Association

Legal Definition

protocol

noun

pro·​to·​col ˈprō-tə-ˌkȯl 

1

: an original draft, minute, or record of a document or transaction

2

a

: a preliminary memorandum often formulated and signed by diplomatic negotiators as a basis for a final convention or treaty

b

: the records or minutes of a diplomatic conference or congress that show officially the agreements arrived at by the negotiators