What Does WD 40 Stand For?

What does WD 40 stand for, piece by piece?

The name has two parts, and each one carries a fact.

Because you say each letter and then the number, the name works like an initialism with a number tacked on. It is not an acronym in the strict sense, since nobody says it as one word. For the fine print on those labels, read acronym vs abbreviation.

Where the WD-40 name came from

The formula was developed in 1953 by a small company in San Diego called the Rocket Chemical Company. Its staff was trying to create a coating that would protect metal parts in the aerospace industry from rust and corrosion. According to the company's own history, the 40th attempt was the one that worked, and the lab name stuck.

Workers at the aerospace plants liked the spray so much that they reportedly slipped cans into their lunch boxes to use at home. The company began selling it in aerosol cans to the public in the late 1950s. In 1969 the business took the name of its best known product and became the WD-40 Company.

What does WD40 stand for if you skip the hyphen?

The meaning is the same. People type WD40, WD 40 and wd-40 when they search, and all of them point to the same product. The brand writes it as WD-40, with capital W and D and a hyphen before the number. In a report, a work order or a school paper, use that official form.

• Correct: "Spray a little WD-40 on the hinge."
• Understood but informal: "Grab the WD40 from the garage."
• Avoid: "W.D. 40" with periods, which the brand never uses.

What the name tells you about using it

Knowing what does WD-40 stand for helps you understand what the product is best at. Its main jobs are displacing moisture, loosening parts that are stuck, cleaning grime and leaving a thin protective film. It also lubricates, and that is the use most people know.

Some mechanics point out that a light spray is not the same as a heavy grease. For parts that need long term lubrication, such as bike chains or heavy hinges, they often follow up with a product made for that job. The label on the can lists the uses the maker recommends.

How people talk about it

The name is so common that people use it in everyday sentences without thinking about the letters.

• "The gate squeaks again. Do we have any WD-40?"
• "I hit the rusty bolt with WD-40 and let it sit for ten minutes."
• "Keep a can of WD-40 in the boat for the hinges and clips."
• "She cleaned the sticky label residue off the glass with a little WD-40."

In speech it is almost always "W D forty." You will rarely hear anyone say "water displacement" out loud.

Myths about the letters

A few stories float around about the name, and most of them are not true.

• "WD stands for a person's initials." No. The letters stand for water displacement.
• "The 40 is the number of ingredients." No. It is the formula attempt number.
• "It was invented for fish." No. It was made to protect metal from rust, not as a bait or fish oil.

Other brand names hide a story in their letters too. See what M&M stands for, TNT and more on the brand name acronyms page.