What is the difference between defray, sponsor, and fund?

Solution 1:

The definitions for each of these words intersect at provide money, but each word carries unique connotations that shade the context of that provision . The discrete connotations of each word can be infered from their etymologies, and their current usage.

Defray has connotations rooted in fixing a broken situation:

1540s, from Middle French defraier (15c.),

perhaps from de- "out" (see de-) + fraier "spend,"

from Old French frais "costs, damages caused by breakage,"

from Latin fractum, neuter past participle of frangere "to break" (see fraction).

Alternative etymology traces second element to Old High German fridu "peace," via Vulgar Latin *fredum "fine, cost."

Etymonline.com

Whichever etymology is accepted, the connotation of defray implies that a separate party engages in an activity and experiences costs or expenses that the defraying party agrees to share, often after the fact, but almost always in an ancillary relationship:

Oil money also paid for a huge Soviet military buildup that, incredibly, enabled the country to reach rough parity with the United States. And it helped defray the costs of the war in Afghanistan, launched in the late 1970s. [Armageddon Averted: Soviet Collapse, 1970-2000, Stephen Kotkin, page 16. Emphasis mine.]

Fund has connotations rooted in laying a foundation:

(v)

1776, "convert (a debt) into capital or stock represented by interest-bearing bonds,"

from fund (n.)...

[1670s, "a bottom, the bottom; foundation, groundwork,"

from French fond "a bottom, floor, ground" (12c.), also "a merchant's basic stock or capital,"

from Latin fundus "bottom, foundation, piece of land,"

from PIE root *bhudh- "bottom, base"

(cognates: Sanskrit budhnah, Greek pythmen "foundation, bottom," Old English botm "lowest part;" see bottom (n.)). Meaning "stock of money or wealth available for some purpose" is from 1690s; sense of "store of anything to be drawn upon" is from 1704. Funds "money at one's disposal" is from 1728.]

...Meaning "supply (someone or something) with money, to finance" is from 1900.

Etymonline.com

The connotation of the verb fund implies that the money is a fundamental contingency of the activity, and often that the funding party is committed at a fundamental level:

This chapter is for the way Mr. and Ms. America invest in order to pay the bills, get out of debt, put their kids through college, and fund their retirement. [Living Rich for Less, Ellie Kay, page 83. Emphasis mine.]

The second section describes major sources of revenues for each level of government to fund their services, including revenues that are raised by a government itself as well as intergovernmental transfers. [Handbook of Governmental Accounting, Frederic Bogui ed., Page 130. Emphasis mine.]

In exchange for a senior claim on specific assets of the hedge fund, the prime broker will partially fund the manager's purchase of securities. [Managing Hedge Fund Risk and Financing, David P. Belmont. Emphasis mine.]

Sponsor has connotations rooted in a solemn guarantee:

1884, "to favor or support,"

from sponsor (n.)...

[1650s, from Late Latin sponsor "sponsor in baptism," in Latin "a surety, guarantee, bondsman,"

from sponsus, past participle of spondere "give assurance, promise solemnly" (see spondee).

Sense of "person who pays for a radio (or, after 1947, TV) program" is first recorded 1931.]

...Commercial broadcasting sense is from 1931.

Etymonline.com

The connotation of sponsor implies that the sponsoring party is committing superior resources--often but not always money--to support the expensive or risky activity of another less endowed party:

This program created a legal channel and enabled emigres to sponsor their families in Cuba. [Guantánamo: A Working-Class History Between Empire and Revolution, Jana Lipman, page 200. Emphasis mine.]

We were of the impression that, at this point, the district would give us a go ahead since they already agreed to sponsor our secondary program. [Keeping the Promise: One Charter School's Experience, Samuel Yigzaw.]

Though the words share a common definition, the various shades of meaning in each word makes it more suitable in some contexts and less suitable in other contexts. From the corpus:

• "Money" will most likely fund a program, and less likely sponsor a program, but will never defray a program.
• "Money" will most likely sponsor a team, and less likely fund a team, but never defray a team.
• "Money" will most likely defray costs, and less likely fund costs, but will rarely sponsor costs.

Solution 2:

To defray something is to partially offset the cost of doing that something by also doing something else that generates income, usually as a related sub-activity. (If you are throwing a huge party and you have a live band playing, you could defray the cost of the party + band by selling T-shirts, or by raffling off backstage passes, etc.) Defray has the implication that your income-generation scheme is intended as a way to reduce your net expenses, not a way to make a net profit.

To sponsor something is to provide money to a person, group, or organization, generally in order to enable them to perform their normal operations, in exchange for positive publicity. Usually this happens in part because the sponsor agrees with the sponsored group's ideals or goals, or enjoys their events; for instance, a "find the cure" group or a sporting event.

To fund something is the most generic term: simply to pay the costs of doing something. There is often an implicit expectation that the person or group providing the funds expects to receive some or all of the benefit from the thing being funded, but that's not necessarily the case.