Grammar girl here, today's topic is cement versus concrete.

Guest writer Sal Glen writes, accuracy is important.

You might think concrete and cement are interchangeable, but you'll quickly find that you're mistaken

when some guy at Home Depot rolls his eyes at you when you ask for the wrong thing.

And if you're writing instructions for someone and you use the wrong word, it'll be your

fault when things don't go so well.

Yes, cement and concrete have completely different meanings, and knowing what they

are helps you use them well and maintain your dignity in home improvement stores.

Cement comes from the Latin word cementum, meaning rough cut stone.

While concrete is from the Latin word concreteus, meaning to grow together or harden.

Both words wandered through middle English until they met in 1756 when John Smeaton

used his version of cement to rebuild the Eddie Stone lighthouse.

In 1824, Joseph Aspton patented Portland cement, a powder made of limestone and clay.

He called it Portland cement because when it was mixed with sand, gravel, pebbles, bits

of rock and water, the resulting dried concrete resembled the limestone from the English

isle of Portland.

This is the division.

Cement is a powder that's mixed with other materials in water to create this solid

mass known as concrete.

There's no such thing as a cement overpass, a cement porch or a cement pond.

These are all concrete.

If you stub your toe on concrete, you'll yell like a Cretan.

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