runoff

Runoff is liquid, especially water or rainwater, that flows off or drains away, as in The storm sewer could not hold all the runoff from the recent rains. 

This sense of runoff is often used in the context of environmental science. It often refers to water that flows into streams or back into the water supply rather than seeping into the ground. For example, when farm crops are watered, any water that is not absorbed into the ground and drains away instead is runoff.

This term comes from the verb phrase run off, which can mean to drain or flow away, as in The wastewater runs off into the stream. 

An unrelated but also common meaning of runoff refers to a competition that determines a final winner after earlier contests have narrowed down the competitors. Similarly, it can refer to a contest held to determine a winner when the initial contest did not produce one, such as when two people tie. This sense of the word is especially used in the context of political elections.

For example, a place may hold an election that features five candidates. After the election, the lowest vote-getter is removed and another election is held with the remaining candidates. This process is repeated until only two candidates are left. This final election, which finally decides the winner, is called a runoff.

Less commonly, the verb run off can mean to decide a winner through a runoff, as in The final contest will be run off at the end of the month. 

Example: Due to the use of pesticides in many industrial farms, runoff becomes a major concern for local water supplies.

The first records of the noun runoff come from the 1850s. It was first used in the U.S. It’s based on the sense of the verb phrase run off. 

Water runoff is a common byproduct of human activity and comes from sources such as factories, farms, and even houses. This excess water is usually contaminated in some way, such as with sewage.

Runoff elections are not common in the U.S. Only a dozen or so states use them to decide winners in state or federal elections. Other contests that use runoffs to decide a winner may use terms that reflect the type of contest it is, such as playoff for sporting events and cookoff for cooking contests.

What are some other forms related to runoff?

• runoffs (plural noun)

What are some synonyms for runoff?

• drainage
• overflow
• surplus water

What are some words that share a root or word element with runoff? 

• run
• off
• playoff
• cookoff

What are some words that often get used in discussing runoff?

• water
• sewage
• discharge
• pollution
• election
• contest
• competition

Two of the distinct meanings of runoff are commonly used in the context of water drainage and elections.

The National Weather Service has issued a Flood Watch for our area. Runoff from the rain will cause flooding in low water crossings so be aware of your surroundings. Don't underestimate the power of water– just a few inches of rapidly flowing water can carry away your vehicle.

— Angelo State Honors (@AngeloHonors) September 21, 2018

Georgia 🍑 – important runoff dates!

Last day to resister to vote in the runoff is Dec 7. Please reach out to friends and college students and make sure they are registered! pic.twitter.com/hcIur8bZfn

— Amy Siskind 🏳️‍🌈 (@Amy_Siskind) December 4, 2020

HD28 special election (Nov. 2019) result:
6 combined Republicans 61%, Eliz Markowitz (D) 39%

HD28 runoff early voting result:
Gates (R) 59%, Markowitz 41%#txlege

— Texas Election Source (@TXElects) January 29, 2020

True or False?

In the context of rainwater that doesn’t sink into the ground, runoff refers to the body of water where it goes.