Language Of Confusion: Laundering, Part II

All these words come from the Proto Indo European leue-, to wash, just like laundry. You might be scratching your head at some of them, though.
 
First of all, deluge showed up in the late fourteenth century, meaning a great flood, and specifically the one in the Bible. It’s from the Old French deluge/deluve, which is from the classical Latin diluvium, flood—so Old French for some reason changed the V to a G. Anyway, diluvium is from the verb diluere, to dilute or wash away, the prefix dis-, away, and the rest from lavare, to wash, from leue-. A deluge washes things away.
 
Speaking of dilute, it shoed up in the mid sixteenth century meaning to weaken or remove the strength of, and not meaning to water down liquid until a full century later. It comes from the classical Latin dilutus, which means diluted, and is just the past participle of diluere. So yeah, dilute and deluge come from the same place.
 
And now for a word that either makes no sense or perfect sense: lavish. It showed up in the mid fifteenth century from the Old French lavasse/lavache, which meant a torrent of rain and is from lavare. So how did it get from wash to bestowing profusely? Well, to lavish is to wash in gifts. Apparently. Yeah, I think it’s weird, too.
 
Lotion showed up in the fifteenth century spelled loscion, a liquid preparation for skin. It’s from the Old French lotion, from the classical Latin lotionem, which means pretty much the same thing. It’s from the word lotus/lautus, washed up, which is from lavare. We don’t exactly wash our skin in lotion, but I get how it came from there.
 
Finally, the word ablution, which is not a word we hear a lot. It showed up in the late fourteenth century, meaning it’s older than most of these words, coming from the classical Latin ablutionem, which just means ablution. It’s from the verb abluere, another word for to wash, a mix of ab-, away, and luere is the same as what was part of diluere. Well, it makes more sense than lavish.
 
Sources
Online Etymology Dictionary
Google Translate
Omniglot
University of Texas at Austin Linguistic Research Center
University of Texas at San Antonio’s page on Proto Indo European language