Grammar 101: Leech and Leach

If you have a good-for-nothing acquaintance who is constantly mooching off of the people around him, if this person is always trying to extract resources from others, you might call this person a leech. Or is he a leach? Both leech and leach are pronounced exactly the same way, but just like site and cite, they have entirely different meanings and usages.

Used figuratively to describe a person who acts like a parasite, borrowing or taking money and other resources from you to feed their own addictions and purposes, the term “leech” is intrinsically related to the bloodsucking aquatic worm of the same name. In some earlier forms of medicine (and actually still used, albeit very rarely), leeches were used to remove blood from patients.

It was thought, as far back as 2,500 years ago in ancient India, that bloodletting by leech would cure certain ailments. In ancient Greece, it was thought that leeches could help to balance the four humors of the body–blood, phlegm, black bile and yellow bile–and thus restore health to the body. By extension, we can refer to a parasitic individual as a leech and the act of mooching off of others as leeching.

That Jerry is such a leech. He always tags along when he knows he’ll get a free meal.

Yeah, my brother-in-law is leeching off us again. He’s staying for the weekend.

By contrast, the term “leach” (with an “A”) refers to removing something from a substance by running some water or other liquid through it. When you percolate water through a porous rock like pumice or sandstone, you are likely to leach certain minerals out of that rock. Similarly, if you put a brand new pair of jeans in the washing machine, it may leach some of that blue dye onto your other clothing.

One way to remember the difference between “leech” and “leach” is that the latter is related to the word “leak.” If you have a bucket that leaks, then the water is slowly being emptied from that bucket. In this way, you can connect the “ea” parts of both words to remind you that they have to do with a liquid like water. And then you’ll be left with the “leech” to refer to your moochy friend Jerry.

If you have an idea for a future Grammar 101 post, don’t hesitate to post a comment below and I’ll add it to the queue.

Image credit: Aaron Fulkerson (Flickr)